If you're talking about the Death Scissors enemy, he has a fairly straightforward pattern and you won't need a lot of space to exploit it. In his neutral state, he has a high chance of parrying your attacks, so the safest time to attack him is the recovery period after his own attacks -- either he'll try to snip his scissors at you from above or go for a broad slash when he's level with you. The best way I've found to inflict damage is using Helmbreaker; I'd jump up to avoid his attacks and then perform a wall-jump or enemy-hike off his head to gain greater height before coming down with a Helmbreaker (I believe Helmbreaker deals more damage the higher up you are in the air). He may still parry Helmbreakers as well, but I find it a better tactic than trying to attack him from the ground with sword combos.
Should the Death Scissors float beyond your reach or hide behind a wall, just stay back and wait for him to approach. Taunt to regain DT if you need it. If he's in sight, you can also shoot him to draw him towards you again. It's probably likely he'll attack you when you start resorting to firearms, but hey that's exactly what you want. :)
When he starts to dive-bomb you, stay calm and remain locked-on. As long as you're locked on, Dante will always face the direction that the Death Scissors will come at him, so it's simply up to your reaction speed to roll out of the way in time. No need for spacious footwork, just good ol' reflexes. :)