There are currently three types of healers. Immediate healing, Heal Over Time ( HOT ), and minions ( minions increase a hero’s HP while their attack is only good for clearing split mobs with 1 HP each ). Immediate healing does nothing for 100% HP, undamaged, heroes, but helps heavily damaged heroes the most. HOT does not stack, but helps heavily damage, and soon to be damaged, heroes the most. Minions can increase a hero’s HP above his 100% HP and heals undamaged and damaged heroes the same. New minions also replace damaged minions “healing” any hero without three full HP minions.
Many 5* heroes are HOT, ( I think Kerridoc pointed this out ), so they don’t stack. Tarlak and Alberich’s HOT would overwrite each other. Delilah has both an immediate heal and minions, so she stacks with a HOT hero like Alberich or Tarlak. Even better, Alberich generates mana for Delilah’s special skill and revives dead heros.
==Minion generation==
Just a heads up for people without minion heroes. This is more a feature, then a bug.
Minions don’t heal, so generating new, full HP minions increases the hero’s effective HP.
But as Kerridoc pointed out, running 3+ heroes that generate minions, may crowd out special minions like Red Hood’s ( 7% heal / mana protection ) but is less important when running Thoth-Amon, Delilah, and any rumored general minions coming to an Empires near you.
MY PERSONAL OPINION
Minions can be useful against Arrow Barrage ( War Rule ) so if I was lucky enough to have Delilah, Alberich, Boldtusk and Red Hood, I would level Delilah to 5* 4.80 since she has minions and immediate healing. Alberich to 5* 4.80 since he can revive and generate mana. Boldtusk to 4* 3.60 since 4* 3.60 are the most powerful heroes with farmable ascesion materials. As a bonus Boltusk 4* 3.60 takes half the XP of 4* 4.70 so you can use the extra 1*/ 2* heroes to level a second 4* 3.60 hero. Red Hood to 5* 2.60 for farming and war.
The original beta version of Tarlak was rumored to be insane ( think 5* Wu Kong ) but the live version appears to be nerfed. Still his 824 attack stat will give him very very good tile damage for a 5* green hero better than Gregorian ( 729 ), Zeline ( 764 ), Lianna ( 729 ) aaand Lady Locke ( 805 ).