Just because your opponents are weak doesn't mean they are nothing, it was simply because you are already too strong for them and this world.
You the strongest have reached the top and no enemies can slow you down to achieve your path... W-wait what is that your doing, why are you giving all your research to all the people who tried to kill you!
Hmm isn't that the demon Lord's daughter? Wait. No, don't you dare do it.
The outcome transformed the demon Lord's daughter allowing her to rise to the throne.
Strolling in the city to buy food you spotted a man covered in rags hiding his whole body covered by a cloak, and you as a kind hearted person donated a gold coin and you received a thank you.
Later not knowing the consequences that person was beaten and took it into heart and vowed to take revenge against you.
On coming into the empire you were invited inside the palace and were given a reward for your achievements not knowing the mastermind behind the world's future destruction is hiding among the nobles and kings lining the side in front of the emperor happily drinking sake brewed by his wife the Empress.
Somehow the mastermind felt threatened when it observed and saw how monstrous you are and hastened the plan to summon the evil god.
On your journey you walked into a village and was invited inside in one of the houses to take rest, after sleeping soundly snoring, you gave a gift to a little girl and when you left. The villagers who hid their greed grinned with demonic smiles and burned the girl and her family at the stake taking their life.
Unsurprisingly the girl awakened her power and became a witch, overnight the entire village disappeared.
On your way to a distant city you passed by a mage tower and visited inside, the place was old and dusty, the place is likely ancient belonging to the olden times.
When you leave, unknown to you, you triggered a mechanism inside upon entering destroying all the seals placed inside and the being inside who once left the world in wails of death eagerly left the rundown place.
Hiking in the mountains awakened an ancient dragon who slept for milennias, the mountains were like its canopies.
When you were out fishing, you accidently caught a cute little monster, unknown to you it's a spawn of a race who lived deep in the sea and their numbers do not fall behind all the entire continent's population.
Many years later, when an existence from the stars tried to invade the world, it was left with horror as it stared at the monsters walking on this world becoming common as cabbages.
And you the perpetrator is hiding in your own pocket dimension to train, afraid of your numerous enemies who you can't defeat.