Aye, but some are derived from ... whatever the hell scale you want to use! (Not that I'm suggesting you didn't know that).
Modes have some character of their own that's not just from belonging to a particular parent scale. If you were to play the notes within the octave CDEFGABC, finish on a C and then try the same with BCDEFGAB finishing on a B it's clearly different. The Locrian sounds unresolved and damn scary. The triad it's based on is a diminished. They used to call the diminished triad "diabolicus in musica" and it was banned by religious types who didn't believe in the art of the jazzy head-****!
What you will perhaps have noticed is that some scale forms have far fewer modes than the number of notes they contain.
For instance whole tone scales have only one mode, they go WWWWWWWW forever (until your neighbour kills you) and diminished scales (WHWHWHWH forever) have two. Such scales are said to be atonal because they don't contain obvious notes to finish on. All things are equal, that's why they're restless and great for scaring children. If you remove notes from these scales you can make new ones which are tonal even if they are bloody weird. For instance Diminshed can be turned into Hungarian Major by removing a note to give (THWHWHWH) which then has a tonal centre, the first note.
If I couldn't laugh at myself how could I laugh at someone less ridiculous?