It's a huge sword. I'd say make a homebrew sword size larger than Greatsword. Most call them "Buster Class Swords". In this case, "Iron Buster Sword- 1D12+4, maybe +5. Reach, Seven feat. Two Handed, Requires Two Handed Proficiency. On Critical, may deal 1D5 Cleaving. Should target fail an 18 DEX...