Stargate: Every System Lord Ranked Worst To Best

Marduk was a believer in ensuring the perfection of not only his own hosts, but those of his subordinates as well. He started his existence as a lowly ashrak, rising through the ranks once Tiamat started her campaign against Ra. He managed to convince the System Lords to elevate him and in return he would destroy Tiamat. He managed this, almost getting himself killed in the process - but he bisected her and consumed the remains, unexpectedly receiving her memories.

He learned of her experiments to create 'monster Goa'uld', and destroyed the sun of their planet to destroy them. He solidified his position, growing his army while sinking further into madness with his continued cannibalization of others. The System Lords were held back from destroying him by Ra and Cronus.

He was a skilled military leader, commanding vast armies, even in his maddest days. He was a pioneer in security techniques, using forms of ancient Babylonian to secure his secrets.

He eventually became so bad that his own priests rose up against him. They sealed him, host and all, along with the Eye of Tiamat into a sarcophagus - along with a flesh-eating creature. The creature would eat him, then the sarcophagus would revive him - and so on for all eternity. However, he managed to turn the tide and infect the creature, consuming his old host in the process.

He was freed by a Russian expedition through the gate, infecting one of their team. He was believed killed when he caught a grenade thrown by the Russians - though enough survived for Anubis to take possession of the Eye of Tiamat, which he would then use to power his mothership.