Best Strength weapon?

[A Regular Italian Plumber]

Are there any STR weapons that end up better than the Last Will with 2 Flawless luck runes?

[PC Master Race]

Yes. Peacemaker 2H sword with Flawless Luck rune does like 513 attack/damage rating at the 36 STR stat needed to weild it (if I remember correctly).

On NG+ I 2 shotted bosses using Shift.

[A Regular Italian Plumber]

Thank you.