I support this idea!

Can you mind control an opposing duo figure to split into figures that you own? Or do they have to split into the original owners pieces? Earlier in the thread it seemed clear that sideboard isn't a factor and isn't necessary so I am to believe that you can mc a duo to split. Please shed some knowledge, thanks!

From the core rulebook, page 6:

You cannot split, merge, or replace your opponent's figures in any way.

Nothing to add except to say that this is the type of thread I'm on realms for- a question I'd never thought of that I now know how to deal with if it ever comes up. Thanks, guys.

the attempts at humor have been... laudable(?), as well.

I'm mostly just here for the crowd's entertainment.

It just occurred to me that there has been all this talk about sidelines, and I cannot find such a term anywhere in the rules documents, nor can I find any rules governing how exactly it works, what restrictions are placed on it, etc.

Is it possibly under some other term that I am unaware of, or is everything having to do with sidelines just "stuff oranges decided at some point".

Welcome to level 2.

There is no other term for this term that doesn't exist in the rules documents.

There are references to it in the Player's Guide, but the term isn't in the main rule book.

MBstoner, No. Actually there isn't any mention of it I can find in the PG either (using searches for "sideline" and "side line"), the sections talking about replacement characters do not use it either.

@moompix Does this mean that the only reason that things like the Uniqueness rule, and the Prime rule apply to the sideline is because someone said so?

Is the sideline part of your force? Is it some weird 'part of your force sometimes but not others' kind of thing?

I seem to remember being told that there was a LIMIT on how large the sideline could be, where is this stated?

I have been going on the notion that the sideline was part of your force, but am I just totally wrong?

From page 6:

When assembling your force, you identify
these replacement characters although they are
not yet on your force.

and

All players should agree on the maximum number of
replacement characters allowed per force.

So, if I don't want my opponents using any replacements, I can just agree to a maximum of zero? Now their Solo adventurer nonsense is negated because they have no sideline?

I would address this with your event organizer. In the league I run there is no maximum number of replacement characters allowed. This makes fans of Spider-Man and Beast Boy very happy.

It only shows up once that i can find, but it's there. Golden Age Player's Guide, Page 4 (if you're using the Modern Age PG, don't, it wasn't updated last time around) under Replacement Characters:

Individuals can't overrule the event policy with regards to replacement characters any more than they can overrule the events build total.

Page 4 of the rulebook:

BUILD TOTAL
The point value that each character has printed on its base is the number of points it costs to add that character to your force. All players should agree on the build total they will use when assembling their forces.

From the Comprehensive Tournament Rules:

2.6 Replacement Characters: Whatever replacement character policy the event will use should be available in the event description. The default replacement character limitation is 3 per 100 points of the build total, with a maximum of 15 replacement characters per force.

So, if it's just you and a friend, you could say no replacements (They may flip the table and leave, but you could do it). If it's a tournament, the limit is set by the organizer/judge, and isn't agreed to on a game by game basis.