What to read after Snowball Earth, Vol. 3?

Tetsuo and his giant robot companion fought the final battle for Earth and lost. Yukio returns to Earth in an escape pod, but finds the planet totally frozen over! After meeting the survivors of the icy apocalypse holed up in Mishima Mall, Tetsuo makes a few attempts at making friends. His defeat of the kaiju that attacked the mall has made him a hero to the inhabitants, but before he can establish any firm relationships, a new threat appears. Another band of human survivors, led by the mysterious Colonel, wants to seize control of the mall—and they have their own kaiju to do it with!