Hahaha well thank you! Should I post my answer to your post in French too?
Heheh I'll go with English so everyone can follow..
I'd go with 6/16 I think, to make sure your Tail Swipe will go last in the round, and with the extra ~400 hp, it should be plenty to buy you an extra round to deal more damage than what the extra power of 8/18 would have given you.
As for abilities, it always depend on what you're battling.
The main reason why I like this guy, is because he's the ONLY pet in game that is Undead with Humanoid abilities
, which makes him totally AWESOME against Dragonkins (he'll take less damage from them AND deal more damage to them).
For this reason, I'd go with Call Darkness for sure. If I'm fighting a team of more than one dragon, I'll even go with Dreadful Breath instead of Plagued Blood. Plagued Blood and Death and Decay would be best if you're taking on humanoids though.
If you don't know what you're taking on, I'd probably go with Plagued Blood
+ Call Darkness
. This will give you more versatility, (3 attacks of 3 different types), one that will lower enemy healing, one that will grant you some healing. Sounds like a good mix for PVP.