Sousou No Frieren vol 1

The enchanting fairy Fereerin and her brave companions, the demon king, and brought peace to the land. But Fereerin will live much longer than the rest of her former party members. How will she understand what life means to the people around her? After decades of their victory, losing her friends made her open her eyes to the bitter reality and immortality. That is why Fereerin sets out to fulfill her friends' last wishes and finds herself starting a new adventure.