Rasmus and Tyres both grew up in the same large pack, though with different families. They were inseparable best friends from a young age, and, as they got older, that friendship transformed into a romantic relationship as well. So, when they both chose to leave the pack together to start their own pack, it was not a surprise to anyone.
Tyres has always been the more quiet of the two of them, and can tend toward pessimistic. He is a sweet wolf once you get to know him, though. It just takes a while to get to know him.
The Cloud Wardens generally have a fluid approach to relationships where it's common for any specific wolf to have multiple relationships, and for everyone involved to raise the pups together. Rasmus and Tyres have an open relationship, and Rasmus is the main breeding wolf of the pack and takes other mates as well. Tyres does not sire pups, but he serves as just as much of a father to the pups as Rasmus.