Thomas Kelly

Sergeant Thomas Kelly is one of the first characters the player meets in Doom 3. He is at the top of the enlisted chain of command on the Mars Base (Marine HQ). A former career military man, he only expects the best from his men. He gets easily agitated when one "slacks" on his efforts, and typically assigns slacking marines to the worst duties as punishment (such as being assigned to the solid waste facility). He makes that very obvious when you first encounter him. Upon arrival, you are immidiatley ordered to start your first assignment (with no time to settle in) due to the lack of troops. The first thing he says is, "Take your sweet time, marine?" In other words, you didn't make much of a first impression in front of your superior. Fortunatly, it's your first day so he shrugs it off. Though he appears to be somewhat cold, he is very well respected for his duties and leadership. When you encounter him, he explains your first assignment. You must locate a scientist who is missing and never showed to his post (Dr. Ishii, Delta labs researcher) and bring him to HQ unharmed. Sergeant Kelly then sends you on your way.

Not long after you locate the missing scientist, the demonic outbreak occurs killing (and possessing) Dr. Ishii and along with almost everyone on the entire base. Sergeant Kelly, now in Delta Labs, orders all remaining marines to head back to HQ for further orders. You are the only marine to arrive at HQ alive. He seems relieved to see you (though he is only spotted on a monitor screen due to the fact that he was unable to physically reach you) and gives you your next set of orders:

His initial direct order to the player is to link up with Bravo team in order to send a distress call. His role in the game is significant: as he commands the Doomguy with orders different than those from Councilor Swann, he creates a conflict as to what the Doomguy should do. Eventually, however, Swann's orders are shown to be the best ones as they avoid a possible hell invasion on Earth. In any case, it doesn't really matter, since if the Doomguy doesn't contact the fleet, then Betruger does it himself.

The reason for his "incident" still remains uncertain. While some affirm he was working with Betruger and the demons since the beginning (substantiated by the fact that he insisted in contacting the Earth armada to bring them to Mars, maybe knowing it would be taken over by the demons), others think he was captured, mind-enslaved and transformed by Betruger to serve him, and that his zealous attempts at contacting the fleet to get reinforcements were simply basic military logic (realizing that the battle is lost without reinforcements). It should be noted that Kelly's appearance and behavior are subtly different once the player reaches Delta Labs (his facial complexion is somewhat paler and he seems almost disappointed that the player is still alive), suggesting that some alteration has occured to him by that point in the game. This is further supported by the fact that if the player chooses not to contact the fleet, Kelly will angrily start to order the player to send the transmission only to be inexplicably cut off.

After the demon invasion, Sergeant Kelly makes only one more personal appearance, as Sabaoth, a mutated demon with tank treads for legs, armed with a mechanical claw and Jack Campbell's BFG 9000. He is the third boss out of four in Doom 3 and presents a formidable challenge. As if that weren't enough, a while through as you're battling him, floor plates drop out to reveal pools of lava that instantly kill you if you fall in.

A few tips are to shoot the BFG blasts to disrupt them and fire away with heavy weapons. You can use the pillars for cover, but they will sometimes electrocute you. Keep in mind to not get near Sabaoth, as he will also try to run you over or slash you with the mechanical claw. There are various items around the pillars, such as ammo and medikits of both sizes. When the floor plates start to drop out, watch your step as you keep battling Sabaoth. Once the battle is over, you can take the BFG.

Bugs

 * In the French version of Doom 3, Sarge's "final warning" is in English.