Luca is a cruel, sadistic, brutal, psychopathic, and outright murderous maniac with utterly no redeeming or sympathetic qualities. He is domineering and tyrannical to the Highland Kingdom by gaining control over the military power of the Highland Army. In this regard, Luca can be described as a "berserker" type of character. He quenches his bloodlust, as seen when he fatally kills the scared woman, after he lets her act like a pig when he burned the village in Ryube.
He is also shown to be traitorous, selfish, callous and dishonest when he betrays Agares Blight, during his father's assassination with Jowy by poison as part of his revenge for fearfully leaving him and his mother during the attack in Jowston. He has a close attachment to Jillia, due to the resemblance of his mother, Sara. He is unaware of her plans of having him killed, along with her own father.
In ''Genso Suikogaiden Vol. 1'', Luca maintains his treacherous, oppressive and megalomaniacal personality during Jowy's scenario in Chapter 2. He shows his dislike for Jillia when he has a personal conversation with Jowy Atreides, where he interrogates him. Jowy then volunteers to serve as a spy to gain Luca's trust.