What does DEKU and Kacchan mean?
Izuku calls Bakugou Kaachan because of his personality Kaacchan means loud and explosive it's also because Bakugou called Izuku “Deku” which means useless so Bakugou and Izuku have nicknames for each other that fit their personality in their eyes.
Who is Todoroki mostly shipped with?
On AO3, TodoDeku is currently the 3rd most written ship in the My Hero Academia tag. It is the most written ship for Todoroki and the second most written for Midoriya.