Wrong. An unmerged Robin with Fury will not die to Ike no matter what

Now you're adding Fury. I was operating under either TA or L&D. +Spd Ike with Fury still kills her unmerged even with Fury though.

and with the HP+3 seal, Swordbreaker

Can't use Swordbreaker on a green lol.

Merges don't matter, neither does nature.

They do, and your dismissal of them just proves your earlier statement about Arena to be true - you don't pay any attention to it.

With the +1 Spd seal, she can survive Ryoma up to +5

He still kills her unmerged with Fury lol.

However, with Swordbreaker and an Ignis proc, she can kill him up to +10, regardless of nature.

Again, can't use Swordbreaker on a green.

Robin will kill Effie in one shot with Ignis and DB3 until +5 merges,

You can't guarantee an Ignis charge, can't use DB3 if you're using her to count cavalry in other teams, etc. Jesus fucking christ. You're constantly isolating things, I look at everything.

and with Lancebreaker (which you can now get because of free Narcian) she will die up to +9 as long as Robin has the Spd+1 seal.

Lancebreaker does absolutely nothing if Effie is running Wary Fighter. Waste of a slot.