One of the sweetest characters in the entirety of the series; the irresistable charm of Kotomi is potent. Despite her reputation as a national genius and bookworm she seems to have little reason to be studious, and accompanies fellow friends Furukawa and Okazaki with no apprehension. Her social inadequacies are picked up in the first few episodes of the arc, following a short time she becomes reasonably normal and even on occasions, a little funny. As for her being unintentionally funny (and 'moe' people comment) I may have found the funniest scene in the entire series.
Kotomi's penchant for misunderstandings combined with the relaxed pace of her voice is surely the weapon that will steal many a man's heart. For me it is much admiration that grips - to be a natural genius with a real devotion to book reading and yet be so down to earth, surely that is the wise unision of Taoist contentment with the Modern Age?
She only reacts to 'Kotomi-chan' and soon Okazaki discovers the hidden meaning: spoiler (link will open within 24 hours :P)
Her use of Latin is also alarmingly impressive. Very few Europeans have a basic grasp of it.