From what I can tell most of his common movesets all use 100% Accuracy moves, So technically speaking his ability only serves to aiding your opponent hit you, correct? That's really unfortunate as his ability is the only thing deterring me from making an eviolite Doublade.
Not only the your accuracy is %100. The pokémon with No Guard ability;
hits the target
always except some situations such as Protect and type immunities,
hits by
all attacks from target. (That means your target's accuracy is %100 too),
hits the target that has used Dig or fly or Dive or Shadow Force etc. on previous turn.
I think it's a great ability. Don't you think its cool? {XD}