I personally put Life because it keeps him and his puppet alive longer. Longer life means you have more of a chance for that great DOT damage to run its course. Especially since hes not going to be going higher than 2 stars for a while unless youre super lucky. His stats are more defense oriented compared to normal while the DOT will help make up for the attack.

EDIT :and yes his pet scales with HP. Increasing NIN will make him very mediocre and it doesnt directly help anything that Tai wouldnt.
This post was last edited by Hanzo Black at 2016-9-21 13:11 This post was last edited by Hanzo Black at 2016-9-21 13:12