Wreath of Blades and Critical Hits

[Nargrakhan]

Question #1: For critical hits, does the spell Wreath of Blades use natural 20 as per spells or 19–20 as per daggers?

Question #2: For critical hits, would it benefit from using keen daggers in either situation from Question #1?

[Skerek]

Quote:

Saving Throw Reflex half

Quote:

Any creature that starts its turn within the area of the spinning blades takes 1d4 points of damage for every two caster levels (maximum 10d4 at 20th level) and the damage bypasses DR/silver

no attack roll, no crit.

enchanting them is a trap though, you need to enchant each one with the same enchant to gain the bonus on it once with the spell.

[James Risner]

Nargrakhan wrote:

Question #1: For critical hits, does the spell Wreath of Blades use natural 20 as per spells or 19–20 as per daggers?

Question #2: For critical hits, would it benefit from using keen daggers in either situation from Question #1?

Can't crit with a spell or dagger that isn't making a D20 attack roll.