Damage to Salivating Bloodthirster

Need some help.
I wanna distinguish damage to Salivating Bloodthirster before they transform into Hulking Terror. I try to find some events when they spawn or disappeared(and the transform) but didn’t find anything. Then I tried to use their death and found some events that helped me found 2 mobs, that was transform. So step by step I can do what I want but maybe it can be done with one expression?

UPD: find the tabpe in Problem page with this. But also try to do some expression to solve this(can’t exclude overkill damage to see result like in table from Problem)