Bestiary#

Bestiary

Isaac has hundreds of enemies — from basic mobs to elite bosses. Understanding each enemy’s behavior pattern and attack style is the key to clearing the game. This guide is a complete bestiary — including HP, behavior analysis, and kill strategies

Enemy Stat Guide#

Stat	Description
HP	The enemy’s health — reduced when taking damage
Damage	Damage value from contact or projectiles
Speed	Movement speed — affects chase ability
Type	Enemy classification — normal/elite/flying/boss, etc.
Drops	Items that may drop after a kill
Special Mechanics	Unique attack or behavior patterns

Basement Enemies#

The Basement is Isaac’s first floor — enemies are generally weak, suited for getting familiar with the controls

Enemy	HP	Damage	Behavior	Strategy
Gaper	10	1	Fires tears at the character — straight-line projectiles	Sideways movement dodges them easily
Fly	5	1 (contact)	Slowly flies toward the character — the most basic enemy	Just shoot it — almost no threat
Spider	15	2 (contact)	Moves in jumps — attacks when it stops	Shoot it while it pauses — very hard to aim while it jumps
Imp	20	2	Fires arcing projectiles — medium speed	Keep mid-range — projectile trajectories are predictable
Boom Fly	8	40 (self-destruct)	Flies toward the character — self-destructs up close	Kill it early — don’t let it get close. Self-destruct damage is extremely high
Charging Fly	12	3 (contact)	Fires electric shock projectiles — paralyzes on hit	Dodge shock projectiles sideways
Gargoyle	25	2	Moves toward the character — intermittently fires tears	Back away while shooting — keep your distance
Pustule	30	2	Moves slowly — splits into small pustules on death	Kill from range — don’t let it die next to you — the splits are harder to handle
Flea	15	2	Fast jumps — brief pause after landing	Predict the landing spot — attack the moment it lands
Fly Nest	20	1	Constantly spawns small flies — the body doesn’t move	Kill it first — otherwise flies come endlessly
Chest Mimic	30	5 (self-destruct)	Chases the character — huge self-destruct radius up close	Must kill it early — the blast radius is enormous
Blood Fly	10	1	Spawns from blood pools — leaves a blood pool on death	Don’t let blood pools accumulate — otherwise more Blood Flies spawn

Caves Enemies#

Enemy	HP	Damage	Behavior	Strategy
Stone Statue	50	3	Moves slowly — immune to knockback — fires rock projectiles	Flank and attack — frontal shots get hit by barrages
Poison Fly	15	2	Flying — releases a poison gas cloud on death — sustained damage	Kill from range — don’t stand near the corpse
Knight	40	3	Raises shield — frontal attacks are deflected — sides and back are weak points	Circle to the side or behind to shoot — attacking from the front is a waste of time
Shield Bearer	35	2	Moves with shield up — intermittently lowers it to shoot arrows	Attack while it shoots arrows — dodge the rest of the time
Archer	25	3	Ranged shots — arrows have slight homing	Dodge arrows with sideways movement — Archers are weak up close
Egg Head	30	3	Fires colorful barrages — wide spread	Barrages are dense but slow — find the gaps and dodge
Sword in the Stone	40	4	Pulls its sword from the ground — large slash range	Back off out of the sword’s range — attack after it whiffs
Slime	20	2	Leaves a trail as it moves — stepping on it slows you	Lure it to open ground and kill — don’t stand on the trail
Fire Slug	30	3	Fires flame barrages — ignites the ground — sustained burning	Avoid standing on burning ground — dodge fire shots with sideways movement
Rock Worm	45	3	Burrows underground — emerges beneath the character	Dodge the moment the ground bulges — attack from the side

Depths Enemies#

Enemy	HP	Damage	Behavior	Strategy
Ghost	25	3	Moves through walls — semi-transparent — periodically turns solid to attack	Attack while it’s solid — it can’t be hit while phasing
Reaper Scythe	35	4	Fires homing scythes — medium speed — explodes on death	Circle to dodge homing scythes — watch the blast radius
Dark Statue	35	3	Accelerates — fires black barrages — splits on death	Keep your distance — kill it first to avoid the split
Witch	30	3	Flying — fires curse barrages — curses reduce stats	Curses are annoying — kill it first
Skeleton	30	3	Revives after death — must be fully destroyed	Keep attacking after the first kill until it completely disappears — otherwise it revives
Gargoyle (Large)	50	4	Large body — slow — fires three-shot spread barrages	Stand far away — you can fit between the gaps of the three-way spread
Injection Fiend	40	3	Leaves a poison trail while moving — explodes on death	Don’t follow its path — kill from range
Fake Corpse	35	3	Sits still — fires arcing barrages — charges intermittently	Dodge charges sideways — attack during barrage gaps
Owl	25	3	Flying — fires homing feathers — very fast	Homing feathers require sharp turns to dodge — keep moving constantly
Bomber	40	4	Throws bombs — large blast radius — 3-throw combos	Move away the moment you see where a bomb lands — don’t get surrounded

Womb Enemies#

Enemy	HP	Damage	Behavior	Strategy
Blood Pustule	45	3	Fires blood barrages — applies bleeding on hit — sustained health loss	Bleeding is dangerous — bring healing items
Womb Guard	55	4	Fires lasers — laser lines deal sustained damage — moves slowly	Sidestep the laser lines — approach from the side
Flesh Blob	60	4	Splits into multiple small blobs — each one attacks	Focus fire them down one by one — don’t spread your attacks
Infected	40	3	Releases an infection cloud on death — drains health on contact	Kill from a distance — don’t let the infection cloud get close
Bloodline Guard	50	4	Fires blood spikes from the ground — unpredictable	Keep moving — don’t stand in one spot too long
Mind Fiend	35	3	Briefly controls the character — reverses direction — sustained	Control is dangerous — kill it first. Don’t move recklessly while controlled
Dark Angel	50	4	Flying — fires black feather barrages — spawns Black Hearts on death	Black feather barrages are dense — keep diagonal movement
Parasite	30	3	Possesses enemies — possessed enemies get stronger — must be separated and killed	Kill the host first — the Parasite itself is weak
Spawner	45	3	Keeps spawning minions — moves slowly	Kill the body first — otherwise minions spawn endlessly
Blood Pool	40	3	Blood pool on the ground — stepping in drains health and summons Blood Flies	Walk around it — don’t step in

Sheol/Cathedral Enemies#

Enemy	HP	Damage	Behavior	Strategy
Demon	60	5	Fires demonic barrages — summons imps on death	Kill from range — the imps after death must be handled too
Angel	55	4	Fires holy light barrages — homing — drops Soul Hearts on death	Keep moving constantly to dodge the homing barrages
Fallen Angel	65	5	Fires black-and-white mixed barrages — fast — teleports	Teleports are troublesome — stay alert in 360 degrees
Hellhound	70	5	Charges + flame breath — high damage and speed	Dodge charges sideways — stand to the side of the flame breath
Greater Demon	100	6	Huge body — fires fullscreen barrages — summons imps	Need AOE to clear minions — boss-level difficulty
Black Knight	80	5	Shield up + charges — sides are weak — explodes on death	Flank and attack — dodge the post-death explosion
Angel Guard	60	4	Flying — fires golden barrages — holy shield	No damage can be dealt while the shield is up — wait for it to drop before attacking
Shade	45	4	Invisible — only visible when attacking — vanishes after attacking	Attack the instant it strikes — predict its position in advance

Elite Enemies#

Elite Type	Effect	Counter
Purple Elite	HP x2 + speed x1.5 + increased projectile frequency	Stay farther away — high projectile frequency means more frequent dodging
Red Elite	HP x1.5 + explodes on death (large radius)	Move away from the corpse immediately after the kill — the blast delay is short
Blue Elite	HP x3 + speed halved + fires ice projectiles (slows)	A battle of attrition — don’t get hit by the slowing projectiles
Black Elite	HP x2 + Black Heart explosion on death + fires black barrages	Kill it first — Black Heart explosions hurt — watch out
White Elite	Immune to specific damage types — requires switching weapons/tactics	Test which attack works — use a different attack method
Gold Elite	HP x2 + drops lots of coins on death	High economic value — prioritize when strong enough
Glowing Elite	HP x1.5 + fires homing barrages	Keep moving to dodge the homing shots — don’t stop
Stone Elite	HP x4 + immune to knockback + damage halved	Patience — grind it down slowly — don’t rush

Boss Bestiary#

Basic Bosses#

Boss	HP	Attack Pattern	Weakness	Strategy
Monstro	100	Jump slam + spread shots	Recovery frames after landing	Dodge the shadow — shoot during the window after landing
Gemini	60+40	Big red orb + small green orb — attack separately	Kill the small one first — the big one slows down	Kill the small twin first — after the green orb dies, the big red orb becomes slow and easy to dodge
Duke of Flies	100	Constantly spawns flies — fires fly barrages	The flies themselves are weak	AOE the flies — the body is weak — kill it quickly
Greed	120	Fires coin barrages + summons minions	No shield on the character’s right side	Attack from the right — dodge coin barrages sideways
Deformity	130	Charges + fires homing barrages	Recovery frames after charging	Dodge the charge sideways — circle to dodge homing barrages
Pest	120	Poison barrages + poison mist	Limited poison mist range	Keep your distance — lure it to open ground
War	150	Fire bombs + charges + fire rain	Brief pause after charging	Dodge the charge — the gaps in the fire rain are safe zones
Death	160	Homing scythes + teleports + summons ghosts	Position is predictable after teleporting	Aim immediately after it teleports — circle wide around homing scythes

Mid-Game Bosses#

Boss	HP	Attack Pattern	Strategy
Isaac	200
Satan	250	Laser + claw swipes + summons demons + barrage hell	Attack the hands in the first form — attack the head in the second form — attack when it stomps
???	220	Tear barrages + poison gas + teleports	Poisoned floor — don’t stand in the gas — reposition after it teleports
The Lamb	240	Barrage hell + spikes + summons spinning scythes	You can stand between the gaps of the spinning scythes — barrage hell requires constant movement
Mom	250	Mom leg stomps + Mom eye laser + tear rain	Sidestep the laser’s line — find a safe spot during tear rain — attack the heart body
Mother’s Nest	600	Fullscreen barrages + lasers + summons tentacles + scale armor	Scale armor reduces damage — burst it down after the armor drops. Prepare healing items before a war of attrition

Final Bosses#

Boss	HP	Attack Pattern	Strategy
Super Satan	350
Giant Baby	350
The Witness	800	Multi-phase — barrages + summons + transformations — fullscreen attacks	Each phase requires a different strategy. Prepare healing items — this is a war of attrition
The Beast	1000

Enemy Stat Summary#

Floor	Average HP	Average Damage	Threat Level	Recommended Strategy
Basement	15-30	1-2	⭐ Low	Engage directly — get familiar with the controls
Caves	25-50	2-3	⭐⭐ Medium-Low	Start minding your positioning — the barrages get denser
Depths	30-50	3-4	⭐⭐⭐ Medium	Keep your distance — don’t get surrounded
Womb	35-60	3-4	⭐⭐⭐ Medium-High	Kill dangerous enemies first (Mind Fiend/Parasite)
Cathedral/Sheol	45-100	4-6	⭐⭐⭐⭐ High	Top-floor difficulty — needs a good build and good positioning
Void/Chest	50-100+	5-6+	⭐⭐⭐⭐⭐ Extreme	The ultimate challenge — prepare fully before entering

Common Enemy Combos#

Combo	Danger Level	Counter
Fly Nest + Boom Flies	⭐⭐⭐ Medium-High	Kill the Fly Nest first — otherwise Boom Flies come endlessly
Knight + Archer	⭐⭐⭐ Medium-High	Kill the Archer first — the Knight is slow — then flank and kill the Knight
Stone Statue + Egg Head	⭐⭐⭐⭐ High	Both have wide-range barrages — use obstacles to block line of sight
Ghost + Witch	⭐⭐⭐⭐ High	Wall-phasing + curse barrages — dispel curses first — keep moving
Blood Pool + Blood Flies	⭐⭐⭐ Medium	Don’t step in blood pools — clear Blood Flies from range — don’t let them breed
Demon + Imps	⭐⭐⭐⭐ High	AOE clears big and small enemies at once — single-target output gets swarmed by imps

Additional Enemy Types#

Type	Description	Kill Reward
Rolling Boulder	A giant boulder rolling through the environment — cannot be killed — only avoided	None
Wall Spider	A spider crawling on walls — fires barrages — can be killed	Occasionally drops keys/hearts
Poison Spitter	Fixed position — spits poison shots — can be destroyed	None
Flame Pillar	Spews fire intermittently — can be destroyed — drops coins	Coins
Spike Trap	Ground spikes — extend and retract periodically — drains health on contact	None
Bomb Rock	Red explosives — large explosion when destroyed — can blow open walls	Blows open Secret Room entrances

Elite Enemy Stat Modifiers#

Elite Type	HP Modifier	Damage Modifier	Special Effect
Purple	x1.5	x1.5	Projectile frequency +50%
Red	x1.5	x1.5	Explodes on death (large radius)
Blue	x2.0	x1.0	Ice barrages — slowing effect
Black	x1.5	x2.0	Black Heart explosion on death
White	x1.5	x1.0	Immune to specific damage types
Gold	x2.0	x1.0	Drops lots of coins on death
Glowing	x1.5	x1.5	Fires homing barrages
Stone	x3.0	x1.0	Immune to knockback + 50% damage reduction

Enemy Combo Danger Ratings#

Combo	Danger	Description
Boom Fly swarm x4	⭐⭐⭐⭐⭐	Self-destructs surrounding you from four directions — certain death
Ghost + Witch x2	⭐⭐⭐⭐	Wall-phasing + curse barrages — extremely hard to dodge
Fly Nest + Boom Flies	⭐⭐⭐⭐	Endless spawns + self-destructs — the nest must die first
Stone Statue x2 + Egg Head	⭐⭐⭐⭐	Two big enemies + barrage coverage — corner up and pick them off one by one
Slime + Fire Slug	⭐⭐⭐	The floor gets covered in slime and flames — your movement space shrinks

Recommended Items Against Enemies#

Enemy Type	Recommended Items	Effect
Flying enemies	Godhead, homing tears, aura items	Auto-target flying enemies — no precise aiming needed
Shielded enemies	Area damage, orbitals	Ignores frontal shield defense — deals damage from any direction
Splitting enemies	High single-target damage weapons	One-shot them to prevent splitting — IPECAC/Brimstone work best
Self-destructing enemies	Long-range high damage, slowing items	Kill them outside the blast radius — slows give you more time to attack
Invisible enemies	Area damage, homing tears	Know their position without seeing them — auto-attacks hit invisible enemies

New Enemies in Repentance#

Enemy	Floor	HP	Attacks
Miner Ghost	Mines	Medium	Charge + bomb throwing
Mausoleum Guard	Mausoleum	High	Tracking aura + melee
Corpse Worm	Corpse	Low	Poison spray + burrowing
Rewind Ghost	Rewind	Medium	High speed + piercing
Beast Minion	Home	Low-High	Various attacks

Enemy Weakness Summary#

Enemy Type	Best Weapon	Recommended Items
Flying enemies	Homing tears/Brimstone	Homing items — auto-target flying targets
Melee enemies	High-damage tears/bombs	Damage items — one-shot melee attackers
Ranged enemies	High fire rate/piercing	Fire rate items — interrupt their ranged attacks
Splitting enemies	AOE/bombs	Explosive items — clear the splits in one blast
Invisible enemies	Area damage/homing tears	Homing items — auto-attack invisible targets
Boss-tier enemies	Damage + fire rate combo	Damage + fire rate + survival — a well-rounded Build

Enemy Behavior Pattern Analysis#

Behavior Pattern	Description	Counter
Straight-line charge	The enemy charges in a straight line — deals damage on contact	Sidestep to avoid — attack after the charge ends
Homing barrages	Projectiles track the player’s position	Keep moving — don’t stop
Summoning minions	The boss summons minions for support	Clear the minions first — then hit the boss
Area attacks	The enemy releases area damage	Move out of the attack range — use cover
Charge + barrage	Fires barrages while charging	Dodge the charge first — then the barrages