Quote Originally Posted by Platinius View Post

I do have a question, how has Guilliman changed since his return to the galactic stage? Character development and such^^
A higher-ranking lore adept will be along soon* to properly address your query, but as far as I can tell:

Disappointed. In the state of the Imperium and in his father. Every time he meets a brother Primarch** he gets sad and angry. He doesn't even seem to trust Cawl.

*Probably
**Traitors and daemons, but brothers nonetheless