Most cephalopods die after mating. Their sex hormones make them go crazy and they stop looking for food except to eat themselves occasionally. Once the sex hormone glad starts pumping them out, it doesn't stop until they die a horrible death. Live fast and die young.
I was very excited about humanity killing itself off and letting the superior line of sapience take over until I learned this fact. It's going to be a bit before the octopi are ready to create a civilization.
Squid siblings often team up. Very social animals with communication done by color flashing. Humboldt squid have a very high social intelligence compared to a solitary animal like most octopus. Unfortunately that live fast and die young still applies. They need to hunt to grow and they're not adverse to cannibalism. Still, need to be smart to team up and hunt with a crew that will eat you given the opportunity. Ruthless killers and frighteningly intelligent pack hunters that signal to each other which prey they're going after.