Mendo Cino is a Card Professor in Yu-Gi-Oh! R. "Mendocino" is also a pre-release codename for the 300 MHz P6 Intel Pentium II Centrino chip.
Cino was hired with many other card professors to guard the R.A. Project by Yako Tenma. He was disappointed that he met up with Katsuya Jonouchi, as the reward for beating him was only $500, while the reward for beating Yugi Mutou was $2,000,000. Insulted, Jonouchi suggested that Mendo just hand over the card key if he didn't want to Duel. Mendo answered that he couldn't, as Yako's orders were to defeat any other Duelists that accompanied the Duel King; if he did defeat Jonouchi, he'd get the chance to Duel Yugi. Calling Jonouchi a "cheap Duelist", they began their Duel.
Mendo gained an advantage with his combination of "Dreadscythe Harvester" and "Labor Pain", but Jonouchi counters with "Jinzo". Mendo complimented Jonouchi on doing his best and even admitted he was surprised at the appearance of "Jinzo" and was actually having fun. Jonouchi turned the Duel around using "Shield & Sword" and "Time Machine" and ultimately defeated Mendo. Mendo was shocked that such a tough Duelist would only be worth $500.