Comrades are essentially only for letting you clear raids slightly faster. They do not increase your damage.
Comrades can be hit by the boss' attacks and can flinch, but they cannot die.
In a future update, a new Level 100 Solo Battle "Crimson Ship Graveyard", if you have any permanent Comrade out, your character gains +20% Movement Speed and Enhanced Stamina Recovery for this battle.
Quotes
Only Arcana and Neamhain comrades can speak.
Arcana
In battle
"How exhausting. I'd love a nice, relaxing dip in the hot springs. And before you ask, no. You're not invited."
"Did you just laugh at me? Watch it, or I'll point out your mistakes every chance I get."
"You're the worst mercenary I've ever met. We'll talk about extra training later."
"Hmph. You may as well go take a nap for all the good you're doing."
"Keep it together. Every time you get hurt, I have to work harder."
"Are you still here? I'm getting lonely fighting all by myself."
"Keep your eyes on the battle. And don't disappoint me."
"You'd better be grateful that I'm fighting on your side."
"I only just realized... You're very annoying."
"How much longer do I have to help you?"
When you bump into her ( ͡° ͜ʖ ͡°)
"I know you're doing that on purpose, and I expect an apology."
"How many times are you going to do that to me?"
"What exactly do you think you're doing?"
"I should to teach you some manners."
"Did I say you could touch me?"
"Back off before I make you."
"You're irritating me."
"Don't be clingy."
"Really?"
"Ha!"
When hit
"I-it doesn't hurt!"
"Why, you!"
"Oww..."
When you are incapacitated
"There's no way you would fall... This can't be... You can't leave me alone. Get up!"
"Is this a prank? Hurry and get up... Open your eyes. I'm sorry, just get up..."
"Huh? H-hey... Get up... Get up! Don't leave me alone like this..."
When you are revived
"W-why are you getting up now? Whatever. I-I wasn't worried about you!"
"Y-you're awake? Oh... nothing."
Neamhain
Standing
"I'd love to go on a picnic instead of to war... O-oh, I was just talking to m-myself!"
"You can't do this alone... I'm staying with you because I... I pity you."
"Leaving me like this..."
Standing, with mirror
"Adorable, right? N-not me, the mirror!"
"Ahh, my precious reflection..."
"Mirror, mirror on the..."
Sitting
"I'll have a seat, too."
While seated
"Why don't we go to the Sea of Reflection to warm up?"
"I'm hungry. When do we eat?"
"Neit is so soft... Hee hee..."
"My Neit bear... So cute!"
In battle
"Humans have come a long way... a long way indeed."
"What must I do today... Oh, no, I don't mind helping!"
"Are we going shopping? I could use a new outfit..."
"My days of godhood are behind me now."
"Your strength is just... it's unreal."
When you bump into her ( ͡° ͜ʖ ͡°)
"You need to be more gentle with me!"
"Hey! Watch where you're going!"
"You're bumping me on purpose!"
"You just... keep getting so close."
"W-what are you doing?"
Hot spring
"I'm not saying I like this... but being here is... yeah."
On the boat
"I look forward to working with you."
"I'll show you my strength."
Comments
https://streamable.com/6nuwh
Abom has 6.693.750 HP, while shield is up, you do 80% damage.
Arcana has 13.000.000 HP
Claire has 16.250.000 HP (for those wondering, full list can be found at Season 3 Bosses Stats and Caps by All Might)
In 5 mins, your Neam did 1 bar of shield, 1.75 bars no shield.
Your Succ did 1 bar of shield, 1.2 bars no shield.
6693750/10/80*100 + 6693750/10*1.75 = 2008125
6693750/10/80*100 + 6693750/10*1.2 = 1639969
My Neam did 1.75 bars, Succ did 1.4 bars
13000000/10*1.75 = 2275000
13000000/10*1.4 = 1820000
The results:
Your Neam did 2m damage, my Neam did 2.2m damage
Your Succ did 1.64m damage, my Succ did 1.82m damage.
My comrade's damage are actually both almost exactly 10% higher than yours.
I suppose the difference is either my stats are higher, or I used the corner damage as the comparison (because corner is much more similar to your edge damage than center).
But based on the tests you did and mine, neam is definitely superior, worth the money.