I soloed these until 19 when they became mostly green. They swing about as fast as a falcata, which can be a little tricky, plus they parry and double hit sometimes. However, as a Ranger, most of their hits had (-2) on the end. You also get damage bonuses for hitting them with piercing damage, which is good for piercing weapon using Rangers and bodkin arrows, if you can't afford broadhead (which still do more damage without the bonus). I recomend flight bodkin though (or footed flight bodkin or even footed flight broadhead if you're rich) because the place I found the most of these at was very spread out and the gurites are moving 90% of the time, making length a bit more important. I've killed a ton of these and never got the listed mace, but I did get many "worn shadow" items, which included a possibly complete set of leather armor and a rapier (and maybe other weapons that did drop). Plus they dropped Siabrian bracelets, which are pretty good, especially for the ranger with naked wrists. The only real problem is that even though the area is big, it really only serves one. If there's a group or a person or two there before you, it may be hard to share. That's rare though, even on Guenivere.
Hunted these guys from 16-17 and will be back for more. Soloing is easy if you use crushing and wear reinforced. As a druid I did yell-high yell w/just barely less than half health, and had time to heal after. Take horse to Innis from howth/connla and jump off at the "fruit stand" along the road. NO BIND POINT! Caution, they will aggro, massivly, and move pretty fast. No debufs/poison/disease to worry bout, and Very under camped. Pls don't spoil that. Good loot too. Leather armor 30/10 no bonus but yell to 17, (i wear reinforced) and piercing weaps, good as bristles tooth, but no stat bonus's. No need to group this one, as it's easy to pull a single. lvl cap on mobs near stand and trees is 17, I know orange went yell at 17, and yells went blue