AnonymousBlank said:
1. "Being in Ireland puts Cu above Diamuid who is >= King Arthur skillwise."
2. "Achilles > Siegfried"
Fate Dojo Q&A:
Q: Cu Chulainn and Diarmuid are both Lancers, but who will win in an honourble battle? In their first engagement with Saber, Cu Chulainn was being pressed hard, but Diarmuid was able to pressure Saber. So... Diarmuid is stronger.
A: Diarmuid received more backup from his Master (magical energy supply), thus in terms of pure firepower, Diarmuid was stronger. In Japan, both of them received 0 geographical boost (from the cultural sphere), but if the stage was in Ireland --- Cu Chulainn would have an edge.
1.Being in Ireland gives both of them a stat boost and due to Cu's fame in Ireland he'd get an even higher stat boost to make up for his shitty master. And that would definetly put him above Arthur summoned in Japan. Also it doesnt even say Cu is straight out weaker(in terms of skills) than Diarmud.
2. Atleast according to the TypeMoon Wikia, Achilles was fighting equally with Siegfried. (Considering I dont have the option to look up "Fate/Apocrypha Volume 4, Chapter 2" rn, I cant confirm whether thats true)
In the end Cu still has runes, which can create barriers strong enough to defend against high level NPs and he can force his opponent into honorable combat, if Achilles tries to kite him from his chariot.
We also have no Idea who has the advantage in strength here, because in the end all of Cu's stats and his two extra NPs are a mystery, when summoned in Ireland.
Regarding their strength, Cu, in Ireland, is above(in terms of pure firepower) Diarmuid, who, if summoned in a country he doesnt get a stat boost in, already has B-Rank Str.,
but Diarmuid would also get a stat boost, if they were in Ireland.
In comparison Achilles has a B+ in Strength.
Due to both having "Battle Continuation A" I would say inconclusive, because even if Achilles were to outclass Cu in skill and speed, Cu would still have the ability to use Gae Bolg after technically dying as a last surprise attack.