Fun fact:

I wrote a smut xCybertronianReader fic about Max. (⸝⸝⸝╸▵╺⸝⸝⸝) You can read it on AO3...

Canon

In IDW he's a kinda... seriously traumatised guy. Love him for that. He was the prison warden of Garrus Nine (I have so many opinions about Cybertrons judicial system.... primacron...) and he got tortured for A VERY LONG TIME by Overlord. That's why I don't like Overlord. He ends up on the Lost Light, but at some point he becomes the Duly Appointed Enforcer of the Tyrest Accord and he and Red Alert go to live on Luna 2 together. Ahhh maried life. Cerebros is there too but you never really see him.

He appears in other continuity too, which is very fun. I've only seen him in the Power of the Primes shows.. He gets to be a Titan in there! So cool... Sigh...

Not Canon.. Yet

I think Fortress Maximus was in Cyberverse. He's a Titan, and he just roams the surface somewhere where no-one will find him. He gets to hang out with my Seeker oc, who is.. you guessed it! A city-speaker!