Otis Washington

"Don't cut me off like that, it's rude!"

- Otis, on Frank hanging up on him

Otis Washington is an elderly mall janitor and longtime worker at Willamette Parkview Mall. While not crucial to the cases, he tells Frank West about things happening in the mall through a transceiver. He never leaves the security room, and is highly trusted by Frank West, Brad Garrison, and Jessie McCarney.

72 Hour Mode
If Frank West is able to make it to the second floor of the Entrance Plaza, then he will show up in the security room, where Brad and Otis are present. If Frank is unable to make it to the security room, then it is Otis who saves him from the zombies, where Frank gives his thanks to Otis. Nonetheless, after Frank shows up in the security room, Otis is ordered by Brad to weld the security room door shut, blocking access to leaving and entering the security room. After Brad decides to go back into Willamette Mall through the air ducts, Frank follows him, much to the disdain of Otis. But he concedes the fact that he can't stop him, and bestows upon Frank a spare transceiver and an intricately detailed map of the entire mall, from Leisure Park to the Maintenance Tunnels. Throughout the three days Frank spends at the mall, he sporadically sends Frank information and the location of survivors and scoops via transceiver.

After the three days are over and Frank West discovers the true origins of the Willamette Incident, Special Forces arrive, aiming to wipe out all life from the mall, zombie and human alike. While Frank is away from the security room, he finds a note on the desk near the security room monitors from Otis: "Frank, while you were out some crazy people snuck in from the rooftop and started snatchin' people. I heard a helluva racket coming from where the monitors are, so I'm taking advantage of the confusion and stealing a helicopter! I might not look the type but I've got a small aircraft pilot's license. I haven't seen Jessie. There's no time to look for her now. I've gotta get out of here while the gettin's good. I hope you don't think I'm a coward. If we meet on the other side, I definitely owe you a drink. Good luck, Frank."

- Otis

On the note, it says that he discovered a way out of the mall through one of the military helicopters the Special Forces left behind. Using the helicopter, he, along with all the survivors Frank has saved thus far, flies the helicopter and is able to escape the mall to safety.

Infinity Mode
Otis is one of the first enemies encountered in Infinity Mode, fought atop the mall's roof near the security room wielding a frying pan. He is an ideal target since he has raw meat and is found from the beginning until 7 hours into Infinity Mode.

Trivia

 * Despite being one of the most talkative characters in the entire game, Otis' voice is never actually heard, except when he screams when killed in Infinity Mode.
 * Otis appears to find the situation "fun", and says to Frank that he can't sleep with excitement.
 * How he managed to fit every single survivor into one helicopter is unknown, he may have flown one group away from the town and then turned back to pick up the remaining ones.
 * There is a weapon glitch involving Otis' calls. When Otis is calling you, make sure you have a semi-automatic gun, such as the Real Mega Buster one inventory slot away from your current weapon. Answer the call, then switch to that weapon. Make sure that when you answer the call and switch weapons you are running. When you hold down the fire button, your weapon will fire as fast as a machinegun. You have to stay running or the glitch will stop.
 * Otis has an uncanny resemblance to Fallout 3's Walter.