>>718029820
>>718029942
The way you're describing the question doesn't make sense. It sounds like it's between a life doubler and pic rel
>At the beginning of your end step, your life total becomes half your starting life total, rounded up.
These two effects don't interact with each other. Say you go through your turn and gain 20 life up to 40. You go to your end step and your life total becomes 10, half of 20, your starting life total (or 20 half of 40 if edh)
There's no interaction here, you just lose the life you gained over your turn.