is there any way to getting a diamond with pure nexus?

[SpaceScrew]

It seems I must use medal to get access to nexus stage. so must I grind medal from other stage for getting nexus area? high score should be achieved by tactics not grinding.

[Just a robin]

Originally I was going to answer the question as written, but then I got to the hot take at the end.

The way most of the towers are designed, the tower plays out very differently depending on whether you're coming in with medals or not, and not just in terms of how high your stats are at the beginning (although that's a big part of it).

As an example, in tower #12 (Pop Tactical Lord), reaching the Nexus Stage requires not only medals, but it requires that you hold onto all copies of a certain type of key that you find throughout the tower itself, preventing you from opening certain doors with that key. In a Pure Nexus run, you know you can't get to the Nexus Stage anyway, so you're free to use those keys for other purposes. This gives you access to equipment in a Pure Nexus run that you don't have access to in a Nexus Stage run, and as a consequence, this changes your routing throughout the entire rest of the tower.

You don't even need to compare a Pure Nexus run to a Nexus Stage run, you can see these gameplay changes appearing with something as simple as Sunstone count. In tower #2 (Tactical Tower NEW), putting 10 Sunstones into ATK will allow you to get the Golden Feather on the first floor before you leave, which may change how soon you decide to try to return to this floor. Bringing just a few Sunstones into tower #5 (Tactical Trip Mini) will change what qualifies as the "optimal route" in that tower fairly drastically.

I don't think requiring medals is about grinding, I think it's about making the point that proper tactics involves having a thorough understanding of how to make the most of the resources you currently have available. What you're trying to accomplish at any given point will change as a result of how many medals and Sunstones you have, and as a result, returning to a tower with more resources will change how the whole tower feels and plays.

[Deejo Wellens]

There is no "grinding" in this game as properly understood. Grinding is doing something repetitively (and often mindlessly) for a reward. You cannot grind in this game because every medal is earned only by improvement, which is never mindless.

If you could get the highest medal without having equipment, equipment would be meaningless, and making anything meaningless would greatly reduce the depth of the game. Yes, you cannot skip ahead to the final form of the tower.

Choosing which tower to attempt to improve on next, and which ones you have the means for, is part of the tactics of the game. It would be a much simpler game if you could just get a diamond on any stage immediately.