Mass was definitely 'head over heels' for him as colonies even pre-transition (for Penn), they so just wanted to kiss but their relationship was seen as 'taboo'. (Will get into this later on.)

Penn is a transgender man, and Mass, despite being the cisgender man he is, fucking loves him no matter what. More than likely he aided in Penn's top surgery and hormone replacement therapy. (Could've also taught Penn how to make his own packer back in the day.)

So married, so gay, so old. One is a huge major tech nerd who also knows a bunch of other sciences.. while the other can play the organ beautifully and is a huge music nerd.

Mass treated Penn's cannon-based wound back in the Civil War, not as bittersweet as for what he has seen (with ONLY the wound in particular... in all of the union he got messed up over the severity) but he sees it as disgustingly beautiful after it has healed.

When they were younger, their relationship had been viewed as 'taboo' as Mass (being born between an English man and an Irish woman) was in love with Penn (who is native Lenape, Erie, and Susquehannock; whilst being adopted by a Kanien'kehá:ka (Mohawk) woman) as of course.. at the time natives (my people. sigh) were seen as inferior and savage. Didn't exactly stop them, though, since they're still in mad love.

Despite how big of a dick both of them are, they're roughly sweet to each other.

Both of them are smokers, and they swap cigarette packs all the time.