Hero, for anyone who doesn't know, is a DLC fighter added to Super Smash Bros Ultimate with a very unique gimmick that separates him from all other fighters: a move that allows him to pull up a Commands menu with a total of 21 different spells and an MP bar that would be Hero's energy when using spells and can only regenerate so fast, meaning if you're out of MP, this character loses a lot of his potential. Now, I'm not going to say I'm particularly good at Hero, but he can be quite complicated to play, and I find I know some things about him that could help beginners learn this character a little bit and could serve as small tips individually for slightly more experienced players like myself. How you play this character is up to you and your playstyle
Don't abuse of fully charged Special Moves!
This is certainly the most essential of the tips in this list. Hero's Special Moves consume his MP, and special moves, if fully charged, eat through a significant amount of MP (Kafrizz (Fireball) consumes 36, Kazap (Electric sword) consumes 40 and Kaswoosh consumes more moderate amounts, but shouldn't be used to attack enemies anyway), which you might need later. Use Specials as you like, but make sure to hit enemies with some regular attacks too. Regular, non-MP-requiring attacks will restore MP equal to 90% of the damage dealt, meaning you can use them to regenerate your magic forces a little bit faster.
Edgeguarding Commands Menu
The way I prefer to play Hero is to try to knock my enemies off-stage so I have time to pull up my Commands Menu and hit them with something stronger than your average Specials. My favorite finishing move is Kaboom. The big problem with the Commands Menu is that the spells are entirely random and their position is too, so if the enemy is right next to you, you're not going to be able to open the menu, look at the spells and select the right one for the situation before your enemy is right on top of you unless if you have godlike reaction time. So I recommend to use the Commands Menu to keep the enemy from recovering or when they're far enough away that you'll have time to process what moves you have at your disposal before you find yourself with a sword or fist in your face.
Kazap vs Zapple
Kazap and Zapple are two of the three variants of Hero's Side Special, Kazap being the fully charged version and Zapple being the medium-charged version. It seems obvious: Kazap is stronger. Right? Not so much.
Kazap is one of Hero's moves with the best damage output and knockback in his entire moveset, which is saying a lot, considering he can call up one of 21 different spells with just one move. Once fully charged, it'll drop a bolt of lightning from the sky that deals 10% damage, then he'll spin around with an electricity-coated sword, dealing 28% damage and quite impressive knockback, killing early if you manage to hit the attack. IF you manage. The problem with Kazap is that it's extremely predictable and takes a very long time to charge, and doesn't have range to compensate. Also, Hero can be hit before he spins, meaning the attack won't complete and you just wasted 40 MP. If you can manage to use it as an edgeguard, where you know the opponent has to go to the ledge or otherwise they'll die, then it's devastating as, as a plus, in most stages and in all Battlefield stages, there are two ledges, each close to a side blast line. When you're close to a blast line, this move is extremely good for getting early KOs. However, the opponent can still grab the ledge, you might mess up your timing, because unlike the other forms, you can't just release the button when you need to, you'll have to wait the entire duration and then it'll shoot automatically, making it hard to time, or the enemy might just shield it. So, in the only case in which this move can be very good, it's not that incredible. Another useful fact is that the lightning bolt that falls down at the start of this move can actually hit enemies, but the knockback is mediocre and can only be useful when the enemy is camping, not moving, and at very high %, like in a Sudden Death scenario.
Zapple is a less impressive version of Kazap, dealing 12% and practically no knockback, but the good thing about this move is just how much range it has. Zapple shoots a beam of lightning in a single direction, and this can reach quite far, allowing you to rack up some damage on your opponent and/or slow their approach. Once the opponent is high on %, you can get the KO with something stronger like a Dash or Smash attack.
Remember the Up-Tilt!
This is a tip based on how useless Hero's Up-Smash is. It has a very small and thin hitbox, meaning there is no potential for hitting enemies beside you, unlike Link or Lucas's Up-Smashes and also has a very large amount of ending lag, meaning it can be easily punished if you use it by accident. It's good if the enemy is directly above you, especially on characters that walk on four legs like Donkey Kong, as their hitbox is larger horizontally, but it you wish to hit someone upwards from nearby, Up-Tilt is far better. For one, it doesn't have ridiculous end lag, and has a considerably larger hitbox in every direction but upwards (in which direction it has roughly the same reach), meaning you can hit enemies above, to the side, and behind you. It also has slightly longer range than Hero's grabs, meaning you don't have to be so close to haul your enemies upwards.