They are the bosses of planets (and Castle Greedy) in all versions of Ristar.
“Kaiser Greedy is the final boss of the game Ristar. Kaiser Greedy is a power hungry dictator...Kaiser Greedy
“Riho is the first boss in the game Ristar. He appears in the opening, scaring some of the Flora...Riho
“Adahan is a boss in the game Ristar. Adahan is a small representitive of the Mole Civilization...Adahan
“Awaueck is a boss in the game Ristar. Awaueck appears and attacks a brown bird during his song...Awaueck