Harmony isn't the only one who hasn't researched her opponent's existence as Sieg hasn't done so for Harmony
Unlike her though, it is not as though he has some inflated ego as to believe that his opponent is some small fry he can beat with ease. It's just because that he feels that it's kind of pointless to do so. Okay well not necessarily pointless, he just felt that he didn't need to since everything that he'll need to learn about her can be learned in the ring when they begin fighting, strengths, weaknesses, how they fight, everything. Plus he's also lazy to do so, that also played a factor into it.
Anyways this match would be a Last Standing Match, he didn't think that he'd get into a 'special' match so soon but he guesses that it's better to experiences these things early rather than later.
Sieg's theme would start playing
He walks towards the ring as he kinda lazily waves to the audience with a pretty neutral expression on his face. He gets in the ring and walks to the center of the ring to meet with his opponent, his red eyes looking up and down at her.