12) The sword glitters and flashes in even the dimmest light, distracting your opponents and giving you an advantage.
Using an attack you roll to hit AC10 and if you succeed you get the benefits of a successful 'Aid another'. Either a +2 to your next attack on that opponent, or a +2 to your AC from that opponents next attack.
15) Gibbering blade. A sword that gibbers and mumbles things man was not meant to know. Always just out of understanding but clear enough to be disturbing.
You can be heard, -5 to all stealth or silent movement. +5 DC for all enemies in earshot against fear effects.
Maybe add a few charges of the fear spell.
Dunno if it's balanced and probably out of the scope of the OP.
A wooden pole 8 to 10 feet in length. Upon a spoken secret command word it unravles like a scroll to reveal a door to a non-dimensional space about the size of a closet or warddrobe. The pole always weighs the same as a wooden 8 to 10 foot pole regardless of contents. The command word can be spoken from inside the space.
Edit: oops, not a sword. Sorry man. I'll make up for it.