subterra boss mechanics (not a strategy guide)

mechanics of subterra bosses (all of them are immune to most cc unless specified):

uther - has fixed damage reduction (think stoneskin aura), and killing his clones raises your team's ad/ap

scylla - all damage is reduced to 1
phase 1: invincible and only uses basic attacks
phase 2: summons snake clones and can be damaged (1 at a time), but heals back to full at the end and revert to phase 1
you can damage her while invincible with a few gimmicks, but none of them are worth

delphos - reduces all healing/lifesteal to 0, and regularly summons meteors that damage everyone on the field, split evenly

rams - summons 2 waves of scarabs and then hell's gate, then repeat; damages himself with each skill
scarabs explode when killed for high damage, but not if killed by cc (muse and blaine are good here)
don't use anything that slows him down, or he doesn't have enough time to kill himself

rek - melee basic attacks and moves slow, but each basic attack deals 55% of his target's max health as holy damage (ignores resistances but not shields); not immune to knock back
knock backs and melee summons both work against him well

crabbie - only damage over time effects can hurt him; summons a box every so often (can be in front or behind him) that if destroyed grants your team damage immunity for a while
don't bother with non-scaling poison effects like lufia's poison arrow or baggins past the low levels

grunk - summons lava on ground that instantly kills any non-flying units, otherwise functions like normal non-awakened grunk

gearz - has some armor/magic resist unlike other bosses
passive places a debuff on a hero (prioritizes non-melee unit) that reduces healing and reflects damage
skill attack deals 100% (probably) of its target's max health as holy damage (with splash aoe) if target is far away, otherwise it does nothing; targets the hero with the debuff
ult stuns everyone and deals physical damage

greeneye - has even higher AR/MR than gearz
skill 1 places vines on all your units that are removed by moving (not necessarily teleport); does extremely high damage (probably 200% of max health) if not removed after a while
skill 2 randomly entangles one unit with a vine that's targetable but has way too much health for a few seconds; entangled unit cannot move or attack (guaranteed death combined with skill 1 unless you have a way to move it)
ult is just normal greeneye ult that heals more