It’s better than you give it credit imo. As Tanbeer said, you can easily charge up Bloodthirst by using Instant Backbite on a monster with Poison Revenge, before going for a RAW Poison Eater. It also has great survivability, thanks to it’s high defense and multiple ways of healing itself.
With defence that massive, a heal is very useful. Also, it’s there for charging fighting spirit again.
70TU mutual poison touch + 160TU detox bite might sound like a lot but you can easily poison it from teammates in a poison team and the detox bite will easily one-shot any enemy even when Jacko does not have fighting spirit. It also heals by 100% damage dealt so it’s very easily a full heal, particularly in PvE.
What we’re looking at here is a very tanky, stun immune monster that kills every 100TU if high HP, 130TU otherwise and 160TU if you want a full heal. Obviously there’s a little bit of setup and awkwardness involved but I feel confident enough to say it won’t be as hard as you think. Never sleep on a full defence monster… defence like that is amazing.
With Instant Backbite it has combo potential with both Poison Revenge, as said, and Toxic Entrance, of which we have plenty after the last update.
If you can’t build around him or afford the 16 cost however, the only way for him to heal himself and get access to Fighting Spirit is 136tu Detox Bite, which gives plenty of time for the opponent to hit him out of it again.
I honestly love the design, and while it’s not a top tier I’m very happy with it. The only change I’d like to see is 130tu on Detox Bite.
Raw poison eater that kills everything when above 70% health, can heal above 70% again if needed and also charges bloodthirst easier. It’ll also have a use of its passive because it will tank hits so when below 70% you just start using bloodthirst instead. And to top it off it has stun immune, it’s a well made monster.
You can use a teammate to poison it and then an instant backstab and Bloodthirst from next turn onwards. Very good is it’s defence. A perfect thing for a posion team like @DevilsMisfortune but not for normal players like me.