Check out the Tier List Explanation for a summary on each tier list placement!
The best of the best, these servants can be put into any team and will vastly improve team performance by a significant margin. Not only are they the most effective at their role, but not including them puts you at a disadvantage.
These servants are among the best at their role. They are not only strong in most generic teams, but can also carry when their team is built around them. Some of them are not as versatile but their specialization is very powerful in the current state of the game.
Strong Servants that offer a lot to the team. Many of them have a few weaknesses that can be compensated by supports.Depending on the circumstances they can reach Tier 1 in term of performance.
These Servants are either extremely strong when there is a team built around them, with mediocre performance and consistency outside of a dedicated team, or they are Servants that perform best with class advantage, but can be picked to round up a team when necessary.
Servants who are solid against against enemies they have class advantages against, but not particularly outstanding against others. Their specializations are either not strong enough, or they are not as versatile as higher tier Servants, and often require much more support to perform at a consistent level.
These Servants are generally outclassed by better options within their classes. They either have detrimental aspects that heavily hamper their performance, or generic skillsets with low values. They are, at the end of the day, still 5 stars Servant and their stats alone make them worth raising over lower Rarity Servants with comparable skillsets.