In the Dream Chojin Tag Arc, Asuraman and Sunshine steal this power so that the Seigi Chojins would participate in the tournament as enemies. Also, during the Throne Arc, Kinnikuman's brother Ataru Kinniku spoke of Genuine Friendship Power (真・友情パワー, Shin Yūjō Pawaa).
During the Perfect Origin Arc, Strong the Budo, aka Chojin Enma, one of the Chojin Gods descended from heaven to protect the Perfect Chojin and oversee the Chojin Hakaba is shown as afraid of the Friendship power, able to defy the levels of Chojin Kyodo established among Chojin, and turn a weak Chojin stronger and willing to purge it. He's then forced to accept its existence.
The Six Spears of Omega Centauri even try to learn the secret behind Friendship Power in the True Devil Chojin arc during their search for Psychoman's Magnet Power. Lunaight was the first Six Spear to achieve this feat, but lost to Wolfman. In this occasion, Curry Cook is shown as willing holding off and hiding his own Friendship Power, enraging himself and acting as a Zangyaku Chojin again, in a desperate bid to prevent the Six Spears of Omega Centauri from studying his power.
Omegaman Aristera successfully obtains this power during his match against Kinnikuman Super Phoenix when Super Phoenix did a God of Intelligence-empowered Muscle Revenger on Aristera. The fallen members of the Six Spears show up one more time and channel their Friendship Power into Aristera, giving him the strength to take on Super Phoenix.
Friendship Power and the Kajiba no Kuso Djikara, the Burning Inner Strength, are closely related faces of the same coin, as during the True Akuma Chojin Arc one of the essential conditions to employ the Burning Inner Strength as its fullest is having a righteous heart full of mercy and empathise with the suffering and the needs of the fellow Chojin.
This carries over in Kinnikuman Nisei, where among the trials for the Kajiba no Kuso Djikara one of the quality tested is the ability to form bond of friendship between chojin.