Darth Raze was reportedly unapproachable, but the reality was that he was accessible to anyone that wanted to learn. He had his specialized skills, but normally people were far too terrified to ask. That suited him just fine, because he strongly disliked others.
He was largely unconcerned with Celeste and her training since she had been assigned to Vahliri. However, Vahliri had authorized for Celeste to receive training from Raze and the Dark Lord agreed to meet her on Korriban.
The Dark Lord sat in a temple chamber, quietly meditating.
@LadyRen