Erebus fun fact!
This got longer then I meant, whoops!!!
He barely ever can be caught without his jumpsuit on! It’s actually multiple pieces, which can be put together to show off different levels of ability. Usually he only wears the core piece--meant for comfort and easy access. Most who need to discharge fast due to too much stored up Psions tend to wear just the core.
Though there is then the additional piece with is the legs and the boots, which are two pieces within themselves but are there for when you are a helm that is only part time but a live on base. So that you can just walk in and lock up for a quick charge of the ship/hive before going back to work. Usually casual clothes can be worn over top (same for the core piece).
Third is that Canon Mituna arm cross over. What it is (at least in this AU) is either a show of a powerful Psion user who has been Overworked and has Broken. Or a working Psions way into cheap darker markets. It clamps around the neck and zips up at the top part. All mean to make the wearer seem locked in, or “Useless”.
Erebus has all of these parts, and has a history of wearing the full suit to get into the HLW head quarters to snag files before getting out. He also had to wear it during his time Out of commission.
These suits are made by Psions for Psions. So usually they are also very good at helping regulate body temperature and Psion flow.
The only time Tune would ever take the whole thing off would be after a death, or if he was too injured to warrant wearing it until he has healed, as it gets stuck and slows down healing.