|This build focuses on trying to use as much of Arthur's base kit as possible. Thanks to Emerald Axe+, his decent Def and not entirely dreadful Res, he makes a solid blue tank. This is mostly useful in Arena Assault where you know what you're going up against because who doesn't want another cheap Reinhardt bait?
Since we're sticking with his budget kit, '"`UNIQ--item-122--QINU`"' is chosen as his weapon of choice. With it, he can tank almost all meta blues with ease (only exception being fully buffed Corrin (F) (Nohrian Summer).
'"`UNIQ--item-125--QINU`"' is a relatively budget option found on 4 Hinata which gives him much needed stat boosts all-around offensively and defensively. His default '"`UNIQ--item-128--QINU`"' can still be kept if a player does not have access to Fury, but this hurts him twofold in that he loses not only Def/Res for tanking, but much needed Spd to help him not get doubled as well. He also appreciates the extra Atk from Fury as well since he will lose out on a handful of player phase KOs without it.
'"`UNIQ--item-131--QINU`"' can be kept as his default option to deal with both tanky and speedy blues, inclusive of Effie and the high Spd Blue Lance fliers (eg. Tana). '"`UNIQ--item-134--QINU`"' is also an option as well to gain wins on speedier axes such as Camilla, variants of Minerva, Amelia, and Titania. It also prevents Hector's Armads' effect from going off, but Arthur will still have trouble dealing with tankier greens regardless of what he takes.
'"`UNIQ--item-137--QINU`"' ventures into less budget territory but can pick up the win on both the aforementioned blues and greens on enemy phase but lacks the flexibility of player phase KOs. '"`UNIQ--item-140--QINU`"' can also be used instead as a cheaper alternative to QR3.
Passive C is left flexible based on team composition although Hone Attack or Hone Speed are both buffs teammates can appreciate for a quick go-to option. His default '"`UNIQ--item-143--QINU`"' is fine, but can be replaced by other assists if preferred.
For his special, either '"`UNIQ--item-146--QINU`"' or '"`UNIQ--item-149--QINU`"' are fine, whichever is available. The former activates more often and helps him pickup wins he barely misses out on without while the latter has a more hefty damage boost due to his 33 Def, picking up even more wins when active.
For his IVs, take +SPD since although his Spd is not exceptional, +Spd will still help him tank more things. With +Spd and Fury, he sits at 35 Spd which isn't terrible. For his bane, -HP is the preferred choice since a bane in any other stat hurts his matchups. Additionally, a -HP bane can be patched up with '"`UNIQ--item-152--QINU`"' or '"`UNIQ--item-155--QINU`"', so it hurts less than other banes.