Kakeru Ozora is the tritagonist of Hearts in Ice. He is an astronomer who finds a piece of Princess Snow Kaguya's comet and takes it to study it further. He is part of a love chain, as he is in love with an astronaut named Himeko, but he is the love interest of Luna, herself the love interest of Artemis.
Kakeru carelessly rescues Luna from getting hit by a car by rolling into the street in the process, and he nurses her back to health. However, he himself becomes in bad health when the piece of the comet goes off, and somehow, because of different beliefs, clashes with Himeko.
After being almost completely drained of his life energy, Kakeru stumbles into the night, hoping to stop Himeko from going into space because of the invasion by the Snow Queen.
Luna appears to him after the Snow Queen is defeated, with the help of Sailor Moon's Silver Crystal, as Princess Kaguya. His energy restored, Luna helps him to realise the truth about his feelings for Himeko, and once she returns from orbit, Kakeru is there waiting for her.
Voiced by Jeff Lumby.