Ouroboros is a snake "eating" its tail. This could be part of life, in that it could keep on living... actually i'm kinda stuck. I think its ok in life.
The idea is good, especially the regeneration in LIFE, which should've been done ages ago.
The balance.... I would love/hate to see it synergise with death... but it's balance is good (low attack will make it fair).
The synergy with death is obvious, but also fitting with the card theme, because Ouroboros represents the creation (the snake's eating) through the destruction (eating it's tail), linked in an endless loop.
Also, i thought more about it, and i agree: Life fits this card, you're right!
I still think that a cost of 2|2 would be more appropriate. Afterall, a simple shield would block it.
OP with Otys, 'nuff said.
Make it like Phoenix, a Rebirth with cost, so it would be more balanced 
An Oty getting +1|+1 every turn is not overpowered, i think.
There are many ways to achieve that effect: Aflatoxin, for example, even on enemy creature, has the same result.
