is it me or Messmer character was kinda wasted??
I can see what you're saying and I agree.
I feel like his role was smaller than it should. And the lore around him a little messy. The DLC didn't know how to balance between him and Miquella; we all thought it would have something between them, since both of there were the focus and also siblings. In the end, it's quite weird how neutral they are toward each other, as if they ignore each other's existence. I think it's just another sympton of two projects being blended into one.
I don't appreciate how disconnected Messmer feels from the main plot, we use him to burn a stick and that's all. When we learned about his kindling, I hoped to see some big importance just like Melina. But you just go there, fight him, and it's done. He's a main boss, but he doesn't feel like one at all?
About his lore, it's really good most of the part. But then, Shadow Keep has almost nothing regarding Messmer. We have the lore of his knights and soldiers through their equipments and a few stuff about the crusade, about Messmer himself is almost none. And when it comes to his main family (Marika's offspring, not Radagon's), it's even worse. They wasted a chance to tell us really interesting stuff such as:
His relationship with Godfrey. We find a talisman regarding Godfrey at Shadowkeep, and we clearly know they were together alongside Marika. And it's not there was a need to confirm paternity or whatever, but just tell us these two men, so loyal to Marika, had a relationship. This is important
Melina being just a sidenote pisses me off. And I understand this can be seen as way to confirm Melina always belonged to The Lands Between, being born at the foot of the Erdtree. But his directly young sister, that shares his vision of fire. Both of them sacrifices Marika has made.
Godwyn, as Melina, was his younger brother. Coming from the same mother. And with whom Messmer shares the most duality and parallels. They literally are the Golden and the Shadows we see the entire DLC. Yet, there's not a single mention between them. We only have a few items locations that can tell us a little bit through speculation.
Morgott and Mohg, like Messmer's biggest conflict is with the Hornsent. He had two younger brothers with the omen curse. Of course it would be interesting to know how it went for both sides.
Instead, the DLC decides to put Gaius, telling us how a son of a different Mother, that came far too late in the story, sees Messmer as older brother. The most odd stretch in attempt to tie the character to the story, since there wasn't anything that justified him there.
So yeah, I agree that Messmer had much more potential. We always saw him as some sort of Lady Maria, as in Old Hunters DLC, and Lady Maria is really massive to that story. Or even Genichiro, since their complexity and morality are so similar. And Genichiro is well established as a deep well made villain. Messmer, unfortunately, just like Miquella, feels very underused ):
I love Messmer, he became my favorite character from the entire game. His bossfight is my favorite and the most fun (I'd make a good use of a second phase). And because I love him so much, I wish he had a bigger role as he deserved, being such a complex and interesting character.