Master Otenko (おてんこ さま Otenko-sama) is a character from the Boktai series. Otenko is the terrestrial embodiment of the sun's will, and Messenger of the Sun. Otenko aids Django on his quest, serving as a mentor. Otenko also played partner to Red Ringo, Django's father.
In the first Boktai game, he was petrified by Carmilla, yet his soul is sealed away inside Sabata. When Django defeated Sabata near the end of the first game, Otenko was set free. During a conversation with Hel, it was revealed that Otenko knew about Django and Sabata being brothers the whole time.
In Boktai 2: Solar Boy Django, Otenko was sealed away in Black Dainn's body. When Black Dainn is purified, Otenko is released. In Shin Bokura no Taiyou (Boktai 3: Sabata's Counterattack), Otenko also decides to sacrifice himself to seal the Eternal, Vanargand, but is saved due to his strong bond with Django. Otenko acts as a mentor and guide to Django throughout the entire series.
Otenko would never admit it out loud but he owes Django his life as Django has saved him on many occasions (at least once per game).
Mega Man Battle Network series
Otenko first appears in Mega Man Battle Network 4 in the Undernet as part of a mini-quest to acquire the "S. Sensor" item and activate the PileDriver, and as a "Crossover Points" Trader in Mega Man Battle Network 5 and the Japanese version of Mega Man Battle Network 6.
In Mega Man Battle Network 5 and the Japanese version of Mega Man Battle Network 6, Otenko appears as a secret Battle Chip that powers up other non-dimming Battle Chips as long as it still exist on the field.