Need ideas for a BT dreadnought NPC in a deathwatch themed Wrath and Glory campaign.

Hey, I hope you are all well.

I am looking to add an NPC to my deathwatch campaign, specifically a venerable, firstborn dreadnought of the Black Templars. He will be something akin to a mentor for the primaris deathwatch marines that the players will be playing.

His name Fredrick the Broken. He has been acquired by the deathwatch for his wisdom and experience.

His main three character traits are:

- He is hard to impress.

- His wisdom is invaluable.

- He is very grumpy, even for a dreadnought and does not take insults or jokes lightly (this I may change before I introduce him in session 1 but for now this is how I think of him).

I am looking for lore accurate ideas to add to him as a character. Little character traits and so on that would make the campaign and the roleplay parts of it a little more dynamic and fun.

I was thinking he starts out disliking the players, seeing them as untrained or perhaps not zealous enough.

Perhaps if one of the players choose a black templar as his chapter (the players haven't chosen theirchapters or created their characters yet. They will do that this Friday in our session 0) he will grow to like that one more and slowly open up to the rest through him.

If anyone has any idea please leave them below, I would love to discuss or think of new ones with you.

thanks in advance.