The Chosen Claw (or Chosen Claw of the Emperor) is the term used for the one the Emperor chooses to be his next in line, his heir, his Crown Prince. While the next Emperor in line can be Hereditary in nature, it is possible for the Emperor to choose who he thinks should be the best choice for his replacement. This appears to be something akin to an 'adoption'.
This however doesn't mean that the Emperor's chosen will necessarily become the next Emperor. He still has to prove himself, and kill or defeat any rival Hrai (clans). It's possible for the chosen to be dishonored and lose favor, and for the Emperor to choose someone else.
Alternatively other clans could decide to fight the chosen one to kill them, and raise their own position in the Kilrathi caste system, in an attempt to challenge the positon of Emperor.
In recent centuries the Kiranka clan has held the position of Emperor, and stopped civil wars.
At the time of 2654, Thrackath nar Kiranka was made the Chosen Claw (bypassing his own biological father Gilkarg) due to a number of victories and the honor he had accrued. But had to fight off any rivals to that position. It is not known if a number of defeats and setbacks caused by Cadet Wing made him lose his chosen status, reverting it back to his father or someone else.
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