Felt like I had to after reading the description.

Has 37% longer melee range.
This one's obvious, considering it's a Demo sword.

Fire rate and damage increases as health decreases.
This is a really great idea, but by how much %? 100% at 1 HP? That'd mean it takes 0.08 seconds to attack at 1 HP, and does 130 damage per swing. Although I do like the next mechanic and think it makes it more balanced.

On kill: heals you 20% base health.
This one works really well with the sword's fire rate/damage mechanic, as getting a kill at 1 HP brings a Demo back up to 36 HP (41 with the booties) meaning the Demo only does about 117 damage (still a lot) and takes around 0.1 second for swinging. This means that if the Demoknight wants to do max damage he has to purposely take damage and risk getting killed, and loses that max damage once getting a single kill. This thing could take some serious strategy to be used to the fullness of its potential. My only gripe with the stats you gave it is no downside. And volvo is definitely going to give it a good few downsides with how many upsides it has. So here's my ideas for some downsides.

-No Random Crits
Because every other sword has it.

-10% of buffs on shields
All shields give a buff that's usually helpful to a Demo, so just take those buffs and take 10% off of them. So the Chargin' Targe's stats would be like "+45% fire damage resistance on wearer" and "+27% explosive damage resistance on wearer"

-10% of buffs on all boots
Same thing as the previous downside, but for the booties. "+180% increase in turning control while charging" and so on.

-50% healing from all sources except for this weapon
This makes it so that if you want to rush in, taking damage to deal more damage, then expecting that the Medic will heal you to keep your killstreak going isn't as good as you'd expect. And... yeah.

Post other ideas for this in the comments.