Thanaton being supremely powerful means he's above the likes of Baras, who is above the likes of Marr, who is above the likes of Malgus, who is above the likes of Jadus, who is above the likes of Nyriss, who is above the likes of Revan, who is on par with the likes of a random Imperial Guard, who is above the likes of Scourge, who has killed a bunch of Jedi, and a bunch of Jedi beat Asajj Ventress(Obi-Wan beat her, for example, and he's a bunch of Jedi) so draw your own conclusions.