Toxin 45

but it is still a mystery about the death of carnage it is possible the aftermath of dark region that carnage might come back and along with mister sinister ,Sabretooth,abomination,and Thanos  feature apocalypse and onslaught also holocaust 

but in iron man's computer it was comfirmed that Kassady was Might not in the symbiote so it's still a mystery
Venom is enemy to Eddie Brock and Gargan also because he is the current venom