Ok. So here's the current lineup of servants and their demographics by nationality including Ruler (who's not in the picture)
Greek - 4
English - 4
French - 2
German - 1
Indian - 1
Jewish - 1
Romanian - 1
Syrian - 1
So what's with the lineup?
Saber Lineup:
Mordred (Red - English) - Dragon-blooded member of the Knights of the Round Table turned into a Saber-faced punk cutie. Has an anti-army ability with a couple of mana burst.
Siegfried (Black - German) - Dragon Slayer with a anti-army ability and mana burst
Verdict: Siegfried will win due to the Dragon Slayer attribute as an advantage. Battle is not a one-sided battle because Mordred's Clarent + her mana bursts when properly used could even out Siegfried's Dragon Slayer advantage
Archer Lineup:
Atalanta (Red - Greek) - Demi-goddess, Comrade of Hercules. Beast Slayer equipped with a bow from the goddess Artemis which an anti-army ability, anti-unit ability and berserker ability.
Chiron (Black - Greek) - Demi-god. Teacher of Achilles and a couple of Greek heroes. Has an anti-unit ability
Verdict: Atalanta will win. Despite the fact that Chiron has strength advantage on close combat, Atalanta has Agrius Metamorphosis which boosts users strength, agility, magic and physical damage resistance to an extreme level. Atalanta's shooting is an anti-army shooting ability which would require Chiron to counter every arrow. Atalanta also has a beast slayer attribute which is stron against centaurs like Chiron. But the battle is not a one-sided battle
Lancer Lineup:
Karna (Red - Indian) - Demi-god, son of the sun god and has an impregnable god's armor. Has a couple of OP abilities like an armor that acts like a mini sun melting anything that touches it, demon piercing blade, divine spear of Indra and ability to shoot enormous fire balls. Unbeatable when there is sun and can fly.
Vlad III (Black - Romanian) - Dracula and has the divinity of the location (because the story is placed in Romania). Can raise rock spears out of any rock or any spear. Has a horse. Gets stronger and he gets a hold of an opponents blood. Strength boosted at night time.
Verdict: Karna wins but not a one-sided fight. Karna has a demon-slaying ability which has an advantage against Vlad's demon attribute. Vlad can lock Karna in one location using spears but spears will eventually melt. Karna's spear from Indra has a Sun and Star attribute which Vlad is weak against.
Rider Lineup:
Achilles (Red - Greek) - Demi-god, also known as the Invulnerable hero which you can't slay unless you hit his heel. Has a couple of OP abilities ranging from his invulnerability, flying chariot with an anti-army ability, stat-boosting abilities to a comet-like burst.
Astolfo (Black - French) - Knight of Charlemagne. Has a lance that with ability same to Honda Futayo's Tonbokiri, an anti-necromancy horn and a hippogryph.
Verdict: Achilles wins a one-sided fight. Guess what? Only Vlad III and Karna have the abilities to fight him in his full power mode in Apocrypha series which are both the strongest character in the series aside from Achilles.
Caster Lineup:
Shakespeare (Red - English) - Famous English write which no skills in Magecraft and Fighting but can make Noble Phantasms. His abilities range from the stuff that comes out of his works, making weapons for other to making what he writes into something real.
Avicebron (Black - Jewish) - A genious Jewish philosopher. Master of golems but requires them to be created before the fight. Can control and army of golems.
Verdict: No fight will happen due to Shakespeare's personality. Ability-wise, Shakespeare has an advantage due to the ability to make things out of his words and the time it takes for Avicebron to prepare a golem.
Assassin Lineup:
Semiramis (Red - Syrian) - Demi-goddess, queen of Assyria and the first poison-based killer ever recorded. Has an ability that poisons anyone that touches her and has bad intents against her. Has a floating fortress that can release army of dragon bones and wyverns, shoots beams and a lot more. Has caster abilites like shooting lighting and other types of magic and can summon legendary beasts.
Jack the Ripper (Black - English) - Serial killer that only kills women which in anime became a young female serial killer which only kills men. Has a poison mist ability that only works against men.
Verdict: Semiramis wins on a one-sided match. Jack the Ripper may have the advantage of speed on close combat but Semiramis' poison ability kill her her *that is if Jack could fly and go to the floating Fortress aka Hanging Garden of Babylon. When Jack is on land, she'll definitely get killed either by the dragon bones army, or the wyverns or the beams that Semiramis shoot from the fortress.
Berserker Lineup:
Spartacus (Red - Greek) - Gladiator. Has lightning-based shield (not shown in the anime but shown in the game). Beyong human abilities.
Frankenstein (Black - English) - Monster. Ability to release lightning and suck up mana if the lightning hits you.
Verdict: Frankestein's victory but not a one-sided fight. Spartacus could win on close combat due to strength and agility advantage but once Frankenstein releases the lightning, it's Frankenstein's win.