Getting into Mischief Theatre, and therefore seeing multiple actors in the same role, has really got me thinking about different interpretations of the same character.
In the spring of 2026, Mischief Theatre's YouTube account posted a silly little in-character video of the Cornley Drama Society, played by the then-current cast of the Play That Goes Wrong, taking a ride on a London tourist bus. One detail about it stuck in my mind. Robert (played by Robert Jackson, who I've seen on stage and who I think is very good in the role) was up at the front, attempting to give directions to the bus driver: perfect, extremely Robert. But at one point he calls the (male) driver 'darling'.
This was really interesting to me! Because I cannot picture the 'original' Robert Grove, played by Henry Lewis, addressing strangers as 'darling'. But, at the same time, it's definitely something I can believe of a Robert Grove. If you take a character with all the traits I'd consider essential to Robert Grove, dial up the flamboyance a little, perhaps play him as gay, you'll get a character who might well call people 'darling' offhand and who I'd still recognise as Robert Grove.
To be honest, I do consider 'has slept with Chris's mother' fairly essential to Robert's character, but I will permit interpretations of Robert as gay on the condition that he sleeps with Chris's father instead. (Lewis's Robert, if you were wondering, strikes me as bisexual; he's had relationships with women but is also fascinatingly abnormal about Chris in a way that makes me suspect there's some attraction there.)
And this 'slightly different interpretations of the same character' thing is something you get all the time in live theatre! Every cast change, every understudy, even small differences in the same actor's performance from night to night: all of these can birth a new version of a character. This is something you'll also get in other media - reboots, adaptations etc. - but it's really baked into the theatre.
Thinking about this led me to realise that this is also something we see in fanfiction. Reading fics about the same characters by two different authors is a lot like seeing two different casts in the roles.
When I read someone else's fanfiction, I might find myself thinking, Huh, it would never occur to me to have that character say that, but I can believe it. It may not be exactly the same character who appears in my writing, but it's still the same character. A different performance, a different translation of the character in the canon onto the page, but one that's just as valid as mine.
These characters hold so much potential for variation, and yet they're still bounded; there's a point at which I'll think, I don't think they'd say that at all, actually (or, in the theatre, I'm not sure this performer has the right presence for the role). The Dennis of The Play That Goes Wrong is better at remembering his lines than the Dennis of The Goes Wrong Show, but they both feel like Dennis. If you gave one of them complete confidence on the stage, though, he'd no longer be Dennis; that would be a different character. It's interesting to think about where the boundaries are, how much you can change while still keeping the character recognisable.
Both theatre and fanfiction are settings that allow a person to take an established character and put their own spin on them. It's always interesting to see the result!