The End of Russet    

Prince Zeroth had a wide arsenal of spells and skills in his arsenal. And two of them were powerful enough to withstand Russet's attacks.

[Dark Sanctuary] and [Obsidian Rampage].

[When activated [Dark Sanctuary], a radiant barrier of shimmering energy surrounds Prince Zeroth, forming an impenetrable shield. The barrier absorbs and nullifies incoming attacks, rendering him invulnerable for a short duration.

Any harm inflicted upon Prince Zeroth during this time is instantly reflected back at the attacker, amplifying the damage several-fold. The barrier's ethereal glow pulsates with resilience, warding off even the most formidable assaults.]

Of course, Ren saved this spell to his [Mind Palace]. It might come in handy in the future.

While the [Obsidian Rampage] was the most offensive skill the Prince had.