Sir Obelisk

A pretty-faced monster slayer for hire. Although he claims to be more of a "Slayer of Evil", elaborating that not all "monsters" are monsters and implying that he'll kill people, too. Although he is relatively well known and respected in his area for his effectiveness in combat, he views monsters hunting itself as little more than glorified pest control. Has a soft spot for "nicer" monsters and when on a job will often attempt a peaceful solution before drawing his sword. Because of this, other monster slayers tease him, calling him a monster "lover", but he doesn't seem to mind. He secretly has been taking care of three half-monster experiments that he "rescued" on one of his first outings from before he was even officially a monster slayer, which he refers to as his little sisters.

Also of note: where he's from, purple is thought to be associated with monsters, hence why it's so prominent on his outfit. Normally this would be considered bad luck, but his track record in spite of this seems to have only added to his reputation.
Yellow is thought of as the opposite; the necklace he wears was given to him by his parents as a protective charm, though it seems more symbolic than anything and doesn't actually have any magical properties.