Funny you should ask. I had been running her with a 3* troop.
I drew a 4* Mana troop for her, and thought Wheeeee!!! and started using it.
She had been making 149HP minions for everybody, I took a look and now they were 141HP minions. WHAT HAPPENED???
Oh. My 3* Devout Battlers, Level 4 added 6% health; the 4* Monastic Battlemages added NO health.
A little later, I pulled a 4* Crit troop (Exalted War Constructs). At Level 1, it only adds 4% health, but the other stats are better, so I’m running with it for now.
That said, the 3* attack troop starts at +5% health, and the 4* crit troop starts at +4% health. Both start at +13% attack. (The 4* has way better defense and crit bonuses) In health, the 3* has a head start. I think it bumps up every 4 levels, so the 4* needs to be 4 levels higher than the 3*
Uhm, at Barracks 6, 3* troops max out at level 20. (Barracks 3 today) At Barracks 9, 4* troops finally can get to 25. So I’d have to nearly max my barracks to get the health bonus of the 3* matched with a 4*. AND I’m pretty sure getting a 3* troop to 20 is way cheaper than getting a 4* troop to 20, never mind 24 where it matches, or 28 where it gets 1% better!
I’ve heard it costs literally hundreds if not thousands of dollars to get the feeder troops needed to max a 4* troop, and I don’t play the game at that budget, so I doubt I’ll ever see that.
I’ve seen discussions of the mana troops showing that in order to get a spell to go off with ONE less tile, you need to get them to level 17 or 23 or something like that.
Any increase of Deliliah’s health gets (effectively) multiplied by 5 with each set of minions she creates. I went into boss stages of the Pirates Challenge with everybody carrying 2 or 3 minions in front of them. For most heroes, attack or defense matter as much or more than health. For Deliliah, health is king.
Oh and attack matters too–the minions inherit a percentage of her attack strength as well as a percentage of her health. But they really are more effective as meat shields than they are as fighters, so health is still on top!
Making a troop just for Deliliah, your best value is probably maxing the 3* troop. For most other heroes, the 4* crit is probably better.