It was nice to see the start of the feud between Magnai and Sadu. Still, I can't help but wish there had been a little more substance - just a little - to the whole series. Now I'm asking "4.1 when?" since I've run out of things to do but level alt classes and grind tomestone gear. "Raid" group disbanded because we couldn't beat Susano'o, and I only joined as a favor to my brother.
The biggest problem I have with the Magnai / Sadu ship is that she has shown zero interest in romance. While there is some back and forth between them, only Magnai has shown a desire to find love - Sadu doesn't seem to care, and they both need to get over their pride.
If one is going to cast Sadu as a tsundere, I'd say she's going to go the classic tsundere route - starts out fiery and defiant, but eventually cools into her role as Magnai's love interest instead of flip-flopping between "fiery" and "lovestruck" like more contemporary tsunderes. That said they'll need to do it quick, since they "only" have 4.1 - 4.x (4.55) to do it.