After a long time of silently practicing with it, while he engaged in all his other activities, Sebastian was finally a pro in using his new unique skill.
Unlike the Water Transmutation unique skill, the Doppelganger and Invisibility unique skill was more peculiar in the sense that it was not exactly fine-tuned for direct battle like his first unique skill.
Of course, creating doppelgangers to fight was a powerful ability, but it was not as direct as the first unique skill.
Also, the invisibility ability emphasized the unique skill's preference for fighting in the shadows like an assassin than the valiant hero stereotype fighting style of the Water Transmutation unique skill.
Perhaps, these 2 unique skills were created taking their creators' personalities into account, and they perhaps explained why the stronger Ocean King was the one who died first, followed by the arrogant Doppelganger and Invisibility King.
