In GW2 is 5409 the highest level you can get without the Unicorn Chomper

Normally, yes. However there are some mystery portal events where you can use the unicorn chomped and are able to promote him, and be able to get max rank.

You just missed your chance, many people took the time to master UC during last week's mystery portal event.  I played him for a little while, and got a few levels, but then I switched to a chomper I know I'd like to play more in the future and that I have access to.  I'm not expecting to reach max rank anyway.

Didn't know you could level up a character to Master when in fact he wasn't obtained through a sticker pack...does he show up within your backyard character selections (potted characters) temporarily or something?

Nope, just when you click to see the detailed character stats, with a ??? for a name and the various data.

the pot becomes visible with your rank around the pot but the characters isn't in the pot

Thanks for the correction, I haven't gone in to look and see for myself.  I've got a few levels on a lot of party characters I don't own, and I hadn't noticed the pot appearing.

There's a good reason I didn't know that, I haven't promoted any characters that I don't have, I've only gotten a few levels on them.

5410, m8.

Bummer, sorry i missed that portal event - I'll have to keep my eyes open for another one :-)

Thanks

So if 5410 is the max (with no UC), not sure what I am missing - all my characters show as "max level reached" :-(