### Instruction: Classify each of the following as either a Nintendo character or a Sega character: Mario, Princess Peach, Sonic, Tails, Doctor Eggman, Luigi, Link, Zelda, Alex Kidd, Donkey Kong, AiAi, Gilius Thunderhead, Bob-Omb
### Response: Nintendo: Mario, Princess Peach, Luigi, Link, Zelda, Donkey Kong, Bob-Omb
Sega: Sonic, Tails, Doctor Eggman, Alex Kidd, AiAi, Gilius Thunderhead