here's a way for lily not to come off as a mary sue in her comic, same for gardevoir when it comes to that move
Having a unique special move only gardevoir can use is fine. Pikachu and Swellow had this when pickachu shocked them both with a lighting bolt to have this protective shield over them.
Dawn used Piloswime and Cyndaquill to make some kind of Fire-Ice ball in the pokemon Contest.
fair enough.
However, the fact she's said it's illegal to use this move, to not make G seem like a mary sue, she'd be taken away from the athorities and Lily in jail for using it, even more so on 2 kids.
If you dont want G to go bye-bye and you locked up? Simply remove the 'this is illegal' bit from the cannon and just say it still drains life energy from both trainer and pokemon. That would cause less hassle overall also. Just show you in some pain and gardevoir panting or something in the next comic to show this has SOME kind of repercussions.
its not much,and why should ibother giving writing advice to someone who won't listen, but i could goin detail how to help lily change her comic up a bit to not come off as mary-sue-ish. i know she hates the term, but honestly, idgaf. Saying you dont believe in something doesnt change the fact itxist. Saying 'i dont believe the earth is round' doesnt change the fact that the earth is, infact, round.
Being a Mary Sue is largely about how the world acts around the character. The world gives the Sue everything relevant to the story, rather than them having to work for it. That's what makes a Sue bad writing, the rest is just symptomatic. To keep the character from becoming a sue there must be complications that legitimately stand in the way of accomplishing that goal. What you propose would work if,
- They were in an environment where there's a constant threat of attack and the exhaustion is a significant vulnerability. Otherwise it's just "we're tired now, but that poses no risk so whatever".
- "Life Energy" is an actual finite resource and using it up decreases or removes the ability for follow up attacks. Otherwise it's "we're tired now, but if we believe hard enough (and we can always believe hard enough) we can play the 'I win' card until it we win regardless".
- The experience is so uncomfortable that Gardevoir shows reluctance to use it even when she needs to. Otherwise it's "sure it made me tired, but it's not that bad. I can do it any time there's even the smallest threat".
Without any of these, or something similar, it's not a material setback. One isn't going to happen because Gardevoir can't be shown getting her ass handed to her after a righteous use her powers. Two isn't going to happen because it's too tempting to make Life Energy an ethereal concept wherein a shortage can be overcome by believing hard enough. Three is ruled out because otherwise Gadevoir would have chosen some other attack, a pokemon looking at you and charging up some energy ball is intimidating enough for a child, and probably still overkill unless those are two very bad-ass bullies.
Regardless, the logistics of a fight between a well trained Pokemon and two children was never going to be interesting in the first place, and Jerry would never write a story that didn't demonstrate his "fixation with fantasies of infinite success, control, brilliance, beauty, or idyllic love"
quoting the DSM 5's entry on narcissism. Personally I take more issue with the portrayal of bullying, and the escalation of force. An exploration of that could have been interesting, but instead we get "These two children are irredeemable. The light poke didn't stop them, bring out the Solothurn S-18".