Irida Chikazane
Chikazane was a favored retainer of Ôtomo Yoshiaki and was made the guardian of Ôtomo Sôrin. When Yoshiaki let out that he wished to name a younger son as his heir, Chikazane and a faction of other Ôtomo retainers surrounding Sôrin assassinated Yoshiaki in 1550. Sorin, although possibly fully aware of Chikazane's intentions beforehand, destroyed him in turn.
References
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005