Abaddon is horrifying... Spoilers for Declassified

Abaddon is terrifying. 323 feet tall, much taller than in Survivor Instinct.

Abaddon was discovered by Monarch inside Devil’s Tower and they built Outpost 77 around it. After KOTM, Abaddon attacked a coastal town on the gulf of Mexico. Abaddon travels through underground tunnels around the world and gives birth to spiders EVERYWHERE. It can telepathically control them. They're a sleeper cell army. Waiting for the command to attack. Every arachnid species on earth came from Abaddon. Even the Mother Long Legs and the giant spider in Mothra's Temple.

Abaddon has inspired many spider myths around the world. Many of them were caused by Abaddon’s minion's ability to crawl inside victims and control them. They then rip themselves out of the corpses. Jorogumo, Anansi and Arachne were all Abaddon and it's minions. Abaddon also seems to be using it's minions to possibly spy on Monarch.

Alpha titans have seemingly gone out of the way to avoid Abaddon. Abaddon is a true destroyer titan. Albeit, it's likely not completely malicious but rather just lets things play out and might be keeping the score.