Yumi Ishiyama (voiced by Mirabelle Kirkland) is the oldest member of the group, being a year older than the others and is of Japanese descent. Branching from this, she owns a suit a samurai armor handed down the generations she treasures very much, as well as being seen with a Totoro plushie in her room. Although sometimes a bit short-tempered, Yumi is very clever and cares greatly about her friends. Yumi varies between reasonable and stubborn at various points; though willing to reveal the supercomputer to the police in order to prevent a nuclear explosion, it takes the destruction of most of Lyoko to convince her to let William Dunbar join the group. For the 1st and 2nd season she is 14-years-old and in 9th grade. In the 3rd season she is (surprisingly) still 14 but is in 10th grade. In season 4 she turns 15 and is still in the 10th grade.