[PC] Looking for Obsidian Greatsword

As the title says, I'm looking for an Obsidian Greatsword because I didn't manage to cut off Kalameets tail in my world (never got any summon signs, so I had to fight alone). I can offer either titanite Slabs (normal, red and white) or boss souls/weapons/armor. Add me on GWFL or Steam for more information:

Steam ID: Folthanos
GWFL ID: Sepulchure13
Soul Level: 102

Thanks in advance