So, making a character overpowered…

Disclaimer: This inspiration is set out for stories in the fantasy genre
I think it’s always a good thing when you try to make a story a bit more exciting to add in an (absolutely) overpowered character to it. Not only is it helpful to add some plot armour to your main character, but also if you want to make the villain more powerful. Now to get down to making such a character, because that might seem quite simple, but to, for example, set realistic limits is a lot more difficult than it looks. Now, let’s get started.

Weapons & Tools
An important factor is to give your character the right equipment and increase their skill at using them by a lot but still make it seem realistic or at least logical that they’re skilled at using them. It always depends on the scenario and the genre of your story, but if you’re writing fantasy, I would advise the use of swords, preferably multiple, and training the character to become an absolute master of the weapon of his choice. If weapons don’t appeal to you, but you also don’t want your character to rely on powers too much, you can go the middle way, which would be magical weapons. The best would be to give the weapon a power that would enhance the characters’ abilities, both physical or whatever else you want to give them. (If your character needs an entirely new magical weapon, stay on this channel for my story with completely customised weapons.)
If you don’t want your character to use weapons for any reason, I would advise you to find some sort of power it can rely on (Combining a weak power with weapon mastery can be valuable).

Powers
If your character isn’t already powerful enough for your taste (or you just want to add powers to your story), magical abilities or other abilities due to high intelligence or training might be the solution to make this character complete. Examples of powers would be spells, enhanced reactions, and simply above normal physical abilities. (But there is a huge variety of powers to give to any character, so if you want a list, tell me somehow.)

Limits
Of course, every overpowered character can’t just interfere whenever they please and save everyone in the story from enormous failure. So, when introducing an overpowered character, look for ways to limit his actions:

• Overpowered abilities and skills, but not a powerful user:
  This is a limitation to the body of the character, which can be used by explaining the required focus or energy for the character using their powers, and therefore not being able to do it for a long time or not very often.
  
• Overpowered, but always busy:
  This is the embodiment of a side character not interfering during a fight and then people ask you where he was, and you just say suddenly he appears next to you and next to him are ten enemies piled up all defeated. You can basically use this by sending the character on a separate quest and only calling them in when in great need.
• Kill him of after his job is done… how hard can it be?:
  To explain this technique, I would need to have an entirely new story, or you could just get creative.