The first officer of the Elsior, Lester spends most of his time either making sure that Takuto is doing his job as a commander, or trying to find Takuto as he goes off on one of his crazy adventures with the Angel Troupe. Has known Takuto since the military academy, and has been with him ever since.
Unlike Takuto, whose skirt-chasing and slacker tendencies are somewhat exaggerated in the manga compared to the games, Lester's personality is left relatively untouched. However, he occasionally comes off as being more stressed out in the manga because of Takuto's personality. In the games, Takuto is somewhat more reasonable.
Lester is said to be the second-best of all of General Luft's students, after Takuto. He seems to excel at identifying enemy formations and ship classes, as well as day-to-day running of the ship. Paired with Takuto, whose talent lies in an uncanny ability to second-guess his opponents and take advantage of any weakness (be it in a formation or the ability of an enemy ship), the two are practically unstoppable. If he has any flaws, it is that he is somewhat conventional in terms of strategy, as opposed to Takuto's unorthodox methods. Takuto appreciates his friend's efforts in running the ship, which leaves him free to get to know the Angels and thus boost their abilities in battle. On the other hand, Lester is also the only person aboard the Elsior who can make Takuto sit down and do all the paperwork he's supposed to.
In the first game, unlike virtually every other character Lester has complete confidence in Takuto's ability to lead despite his occasional irritation at how laid-back his friend is. He spends most of his time on the bridge keeping an eye on things while Takuto spends time befriending the Angels. While many others would resent the fact that they're stuck on the bridge while their superior is off having fun with a group of cute girls, Lester is well aware that the H.A.L.O. System is dependent on the feelings of the pilot. Therefore, the better the Angels feel about Takuto, the better the system responds and the more powerful the Emblem Frames become.
A straight man in the truest sense of the word, Lester takes Takuto's somewhat goofy antics in stride and never hesitates to put his friend back on track. While he is well aware of Takuto's ability in combat, it's the way he is outside of battle that worries him. He is also apparently completely unaware of Almo's crush on him.
Since Moonlit Lovers, however, he is painfully aware that Coco has mentally paired him and Takuto up in the past.
In Galaxy Angel II: he is currently the commander of Elisior and is accompanied by Almo, Noa, and Chitose. He is protecting the gate from the EDEN side. He is also still apparently unaware of Almo's crush on him.
Takuto and Lester also now enjoy verbal sparring. Upon meeting the new main character Kazuya Shiranami, he notes, "He's quite different from someone else I know, eh, Takuto?"
In response, Takuto introduces him with the line, "This rude man here is Captain Lester Cooldaras."
Lester later tells Kazuya, "It's tough having an unreliable captain, but hang in there."
Retaliating, Takuto quickly tells Almo, "It's tough having an uptight captain, but hang in there."
* Lester's first name is derived from an English hard cheese called Leicester, while his last name is from a French cheese called Coeur d'Arras
* In one of the Galaxy Angel manga by Kanan, Tact makes up a story about how Lester transforms into a beautiful woman when his eyepiece is removed, shocking Almo. He is then beaten to a pulp by an enraged Lester.
* The above joke was referenced in the audio drama portion of Chitose Karasuma's cd. She is hosting a radio talkshow, and at one point begins reading letters from listeners. One of the letters she reads on-air asks if it is true Lester becomes a beautiful woman when his eyepiece is removed. She comments that she's heard the rumor, but as far as she knows it is not true. She does, however, admit that she'd love to find out.
* In the Galaxy Angel Perfect Guide, his name is romanized as Rester Cooldaras.