So this is Sebastian Travers. He's the Uncle of Nora Flint and the husband of Iris Travers! He has three off-screen children who also live in Tinsworth (and hey, you, yes you can apply to be one!), but his first born son was a wandholder who died in a skirmish with the rebels. He's a former Hitwizard, worked his way up into the upper part of the DMLE, before defecting to Tinsworth. He is now Tinsworth head of Security.
He is not a person that you want to cross. He uses all sorts of interrogation techniques to achieve his goals, and isn't above all the terrible things you can think of. He needs all sorts of plot.