Historians argue over who murdered him; some even claim he died peacefully.

Most of the characters I like to RP are in someway conflicted in their personality. In Lyrl's case it's because he's absurdly intelligent yet he's received no education and is thoughtless. He's an incredibly stupid genius who manages to fail somehow even while doing amazing feats of brainpower. He simply applies his incredible brains the wrong way, and things backfire on him.

Also I like how his emotions work. Lyrl shows poise under pressure when it's a matter of life or death, but get personal and he loses it. About to die? I can handle it. You may have rejected me? NO WHAT HOW COULD YOU

Lyrl is apparently an INTJ on the Myers-Briggs scale. Aka a Mastermind.

At times, INTJs seem cold, reserved, and unresponsive, while in fact they are almost hypersensitive to signals of rejection from those they care for.

"--you left me to die!" ... yeah, that sounds familiar. I would guess that Vril Dox is an ENTJ/Fieldmarshal. ("arrogant, insensitive, and confrontational" ... "intimidating, hasty, and controlling" ... usually these things are more sugar-coated, aren't they?)

Comparing these two, it seems like Lyrl may come off as less of an asshole just because he talks less. Someone who holds their tongue may be aloof or distant or maybe just disinterested. But Vril gets right up in your face, takes control of the situation and orders everyone around without regards for their feelings. He is the center of attention. He is your asshole boss, and you're definitely going to notice him more (and have stronger feelings about him) than that kid who doesn't say much.

This also is kind of helpful when comparing Lyrl to the various Brainiac 5s. It's kind of funny, but someone talking to Lyrl vs. his superhero relatives would probably gain the impression that the superheroes are bigger assholes. They tend to insult you openly and frequently. Lyrl may think you're an idiot, but he's not going to bother to say so and put up with your whining about it. He has things to do. So his introverted nature is really helpful in making him look better than he is. (Not that I'm saying Brainy is an extrovert.)

As a baby, he starts off as a brilliant but still normal kid in a lot of ways. (For example, he names himself Lyrl after his mother's friend Lyrissa in an attempt to please her, and admires and tries to learn from his father.)
Somewhere after he hits one year old, he goes berserk evil and massacres/mind controls the hell out of people. (Though again, he's emulating his father in doing this. Completely stole the mind control program from Vril. Also, even normal kids don't develop empathy before they hit age 2. See this blog post.)
Once lobotomized by his father, he turns into a normal, not-so-brilliant baby.
We next see him as a teenager, when he offers himself to the bad guy to protect some people he's just met. (Though, frankly, he was going to get kidnapped either way.)
He's threatened/joins of his own free will/is mind-controlled into helping to take control of the galaxy.
But then he helps overthrow the evil plot despite being (only somewhat?) mind controlled at the time.
In the process, he breaks his father's arm as a way of getting him out of danger, even though their relationship is pretty volatile.
He then attacks his home planet in a plot to suck his grandfather's head dry of its knowledge.

So, yeah. He is not a simple person. (People constantly altering his mind state with drugs/starfish doesn't help.) But I don't think he'd allow people to know he's crazypants, so if he comes off as an okay guy, good. He has been playing people since he was a baby. Though it's easier when you are SO PUDGY.