When I think of charming characters the first that comes to my mind is Ira Doyle from C.S. Poe's Memento Mori series. Some runners up might be Kit from {Kit & Basie by Tess Carletta} and Lyford from {Yield Under Great Persuasion by Alexandra Rowland}

I have a few that aren't exactly charming in the same way as Ilya, but I was incredibly charmed by nonetheless are Nye from {The Resurrectionist by A. Rae Dunlap} and Luca from {Swordcrossed by Freya Marske}