Which Servant surprises you that hasn't ended up being popular despite having several elements to be so (good gameplay, well-crafted Lore, relevance in the Story, prominent roles in Events, influence of the Writers)?

In FGO, it is known that there are Servants that easily become fan favorites or those Servants that are quite forgotten even if they have participation in the Story or Events.

However... then we have those Servants that have everything in their favor to be fan favorites, but they don't end up being so (they don't even end up being as popular as one would think). You can even see that a lot of effort was put into that Servant to be popular or that they would be a favorite.

Not to be confused with underrated Servants since those Servants have outstanding moments/roles, but many of them were not intended to be the star or be a fan favorite (but they still ended up standing out or being popular thanks to their roles and participation). Here I am talking about Servants that you can see had many elements in their favor to be popular or are a fan favorite: their Gameplay is well done, their Story is well crafted, the writers promoted this Servant, they have recurring roles in the Story and Events, etc.

In any case... Which Servant surprises you that hasn't ended up being popular despite having several elements to be so (good gameplay, well-crafted Lore, relevance in the Story, prominent roles in Events, influence of the Writers)?

Kukulkan is the clearest example of this (and one that will surely come to mind for many), but I want to see if there are other Servants who suffer the same fate.