Shikaku

A Manipulator in the First Prince's private force, caught in the crossfire of Halkenburg's first ability experiments.

Addendum ch.386His body — carrying the mind of Halkenburg's guard Sumidori after a forced swap — walked to Luzurus's door, shouted 'Long live First Prince Benjamin!', and shot itself. Whether Shikaku's own mind experienced any of it is exactly the question Halkenburg was testing.

Addendum ch.404Halkenburg's post-mortem accounting: the experiment with Shikaku and Sumidori proved that only one of two swapped minds is awake at a time, with the ability's own side holding priority. Benjamin later cites the suicide as evidence of the mind-swap mechanism.