When one is completely exhausted from mana they are incapacitated. This is likely because it was a mechanic in the game. You could power up your spells with extra mana but it'd be balanced with the fact that if you ever hit zero, that character would be knocked out as if their hp dropped to zero. Monsters often had some way to hit your mana so mana restoration items were rather common. 

Thankfully this is the case as carrying Mi'ara has legitimately been one of the most challenging things I've experienced in both of my lives. If she was human it'd be pretty easy, just apply self strengthening magic and princess carry them. With Mi'ara though, her body is too long so it drags on the ground. She is also long enough that its pretty easy to accidentally hit the side of a tree or even make some gaps unaccessible without some fanagling like a dog trying to get through a door with a big stick. I eventually gave up and just built her a shelter in orfer to ensure her safety while I got the necessary mushrooms to restore her mana. 

I really should have made an effort to have collected as many as possible on the way here.

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A few days have passed and I managed to teach Mi'ara some body reinforcement magic. I also tried teaching her earth and fire magic but she has been learning those much slower. Her mana reserves have been slowly increasing which is nice, but they are still rather meager. Mi'ara is much more of a warrior type rather than a mage or mixed fighter, but that doesn't matter. One way or another I'll teach her. Magic is WAY to useful to not be able to use it.

 I think for now I'll have her lean in hard into self buffs as those will have a much more immediate impact in battle. Even if she mastered fire and earth magic within minutes it'll still take time to get used to having new options in combat. I could see her completely forgetting she can upset her opponent's stance by shifting the ground or make her spear head hot so it does more damage in the heat of the moment. With body strengthening she just has to cast it before battle and she'll be able to kick ass exactly in the same way she was before but with 10x the efficiency. Basically it doesn't add a new tool into her tool box, but rather sharpens the ones she already has.

As for me I've already learned how to regrow limbs and completely nullify pain with dragon magic. Of course I learned the second spell before the first because holy hell letting my arm get ripped off would be painful. I've also found out just how much more mana it takes to cast dragon magic. Just casting [pain nullification] and [superior heal] together cost  somewhere around 80% of my mana. Its really costly but its worth every bit of mana. Not having to worry about any permanent damage in battle besides death is a huge relief.

As for neutral spells they are pretty nifty. I've also only managed to learn two neutral spells so far, but they will be real useful in combat. The first one [binding] basically holds anything in place no matter how much it struggles. Was this what the dragon god used on me? I also probably should have asked their name because just calling them the dragon god might get annoying, although my thought process is getting a little off topic. From the knowledge I've been endowed, it seems the spell can even hold down the soul trapping whatever it holds even if they were to die. Might serve as a good form of punishment for the real baddies, never know when you might need to give a villain a fate worse than death after all. The second one is [larceny]. Its an advanced version of a spell that steals belongings off people. The main difference is that I can steal body parts too. Might be funny to steal the toungue of someone from the organization when the eventually start monologing. 

Finally there's the lightning element. It took a lot of fucking about to even figure out a spell. Unlike all the other magic words I've used, It wasn't already known and given to me by some being that has at least some control over reality. I managed to get lucky and landed on a spell called [lightning storm]. Honestly I can't use this like ever, unless I'm in war and have a preemptive strike or something. The spell litteraly calls in a massive thunder storm over a massively wide area and decimates anything below. It also uses litteraly all my mana. Thankfully I actually started collecting those mushrooms so we weren't slowed down by me passing out. Im REAL thankful because not only do we not have much time for delays, but that storm was definitely visible from the capital so there's probably an investigation team already on its way. Now is not a season you'd typically see storms like that on Esu. I absolutely can't be stumbled upon and questioned about the event and how I'm perfectly fine when the rest of the area looks like hell.

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Cornelius PoV

Despite my failures to keep the young lady in check, I've been left off the hook because of the information on the anomalies I've collected. Rumors have already spread around the capital of significantly stronger lizard monsters appearing in the forests. It seems the amount of cases of  mutations are on the rise. The monster-slaying guild is already planning on making teams to find and remove whatever is causing this. After my employers pulled a few strings it seems I'll be put in the lead of one of these teams to gather more information. I'm currently staying in an inn near the right gate, as the expedition date draws near. The day of departure was set back a little due to a large thunderstorm though, so I had to extend my stay. I wonder what caused such a big storm in this season? Some things have been very weird lately and I don't like it. It gives me a small feeling of dread...