Basil

Basilicum, commonly known as simply "Basil," is Iemitsu's young disciple and subordinate. He possesses the blue, rain attribute flame, and has the ability to go into Hyper Dying Will Mode when he consumes special pills made by Iemitsu. Due to being strictly trained since early childhood, he is a very talented fighter. Unbeknownst to Basil, in order for Iemistu to safely deliver the real halves of the Vongola rings to Japan, he was sent to deliver the fake Vongola Rings to Tsuna. During this, he encounters Superbia Squalo, and is subsequently beat, though despite being used as a decoy, he remains extremely loyal to Iemitsu, and helps train Tsuna in order to help the latter control the Dying Will Flame. The CEDEF later sends him into the future as support for the Vongola, and his box weapon is shown to release a dolphin, which he can telepathically communicate with. Basil also has a habit of speaking in an archaic manner; usually replacing "I," "me," and "my," with "thou," "thee," and "thy," and refers to Tsuna and the guardians with the suffix "-dono." This unusual habit sometimes interferes in his way of modern speech. He is voiced by Yuka Terasaki in the anime. (Source: Wikipedia)