Which Might and Magic universe are you referring to?

Did they just happen to save him, or was someone sent there? ;)

Of course, but it wasn't Katerina. They were sent there by the Grand Vizier Brakada's chief advisor, Rezurektra (on the canonical Path of Light; on the Path of Darkness, it's Castor, the ruler of Dej). Moreover, they weren't sent to save Roland, but to destroy the main stronghold of the Krigans, who were regaining their strength after their defeat in Might and Magic VI. During their journey to Eoful, Archibald telepathically contacted them and asked them to also rescue Roland, who was imprisoned in the Colony of Zod. In addition, he magically sent a stolen blaster to help the heroes against the Krigans in the colony.