First off, welcome to Heresy and the rp threads- good to see the active roleplay threads generating interest.
Secondly, Unending Tide has really just started as a story. The characters have yet to even truly have time to interact with one another as they have been spending most of their precious moments trying to stay alive so far so it is a good time for new characters to be included!
Darkreever (the gamemaster of this particular roleplay) tends to be very good at seamlessly accommodating late additions into his storyline using the 'un-named extras' that he includes in most of his works. The basic premise is that your character has been there all along, just has not been spotlighted until now- like an extra in a movie/tv series that suddenly steps forward into the action and becomes a 'named' character in the story.
This allows him not to have to alter his storyline to include new characters (he may not have plans for an immediate second ork assault) and also allows the new character to understand what is going on and be integrated into the group because, according to this premise, he/she has always
been there just has been un-named until that point.
Now, this may mean he limits new additions to more of a rank and file PDF trooper, but a good gamemaster knows it is less about how heroic a character is when he/she starts and more about how he/she becomes
a hero through their actions in the storyline.
If you have questions/need help with your character- don't be scared to send Darkreever a message. He doesn't bite for the most part (well, unless you earn it from your own actions like god-moding, then you might get to see how sharp his teeth are
). It might take him a day or two to get back to you (life being what it is and all) but he is one of the best gamemasters I have had the honour of playing under so believe me when I say it is well worth the wait.