You were playing arms race growth 4TDM in Arras, and this specific necromancer tank happens to be on your team. He is extremely skilled at using it, yet he doesn't upgrade his class to a stronger one. Currently, he has about 25 million exp. He is killing a group of tanks while spamming this sentence to the chat:

NECROMANCER SUPERIOR TO OVERLORD. NECROMANCER SUPERIOR TO OVERLORD.