Luck or Parry.

[Zummi]

What would rather have as your defensive skill for a singleton? I know it's stupid pitting luck against parry but with it, you get a bonus to armor, resistance, and dodge while parry just gives you dodge albeit in greater value.

[Randomizer]

You need both as well as hardiness.

 

Parry is needed for certain encounters with monsters that stun especially the scripted ones that also have a high damage area effect attack that will destroy your summoned monsters. There just isn't a better way to block stun attacks with them.

 

Luck, hardiness, and later resistance after that trainer are all helpful in reducing damage taken.

 

Dodge is useless after the first few areas around the Castle Food Depot. I know from trying it.

[Zummi]

Also Luck increases hit chance. That's another point for investing in it.

[ex post slarto]

Parry does NOT give you dodging ability. It gives you parrying ability. They are very different. Parry chance is a flat chance that works the same against ALL physical attacks. That's why it works on Torment. Dodging depends on the accuracy of your opponent, which is why it ceases working on Torment.

 

It's a moot point, because you need both. However, my advice would be to make an EW singleton and not invest in Parry until you get 3 points from the trainer. Then you only need a few more to unlock the next skill, and you'll still max out its benefits (at 17) before too long.