During a time of crisis, while
Vaarsuvius was alone, they made a deal with 3 archfiends, & so,
the 3 archfiends each spliced 1 soul onto Vaarsuvius' soul, for 3 souls spliced onto V's soul in total.
This Soul Splice had several rules, mostly of negligible effect, which you can read on the 2nd link in this spoilerific text.
As noted above, one of the consequences of the Soul Splice was Vaarsuvius granting the individual IFCC members three periods of a few minutes of time at their disposal. Because Haerta left the splice early, one of those periods is far shorter than the others.
The 3 Archfiends are named Lee, Nero & Cedrick.
To be specific, comic 667 (Missed opportunity, IMHO) reveals that Cedrick & 1 of the other 2 has a period of 20 minutes & 35 seconds & the other has a period of 3 minutes & 6 seconds.
When Vaarsuvius goes, so does V's talking raven familiar, Blackwing, since being a familiar means having your soul bound.
V's soul & V's familiar's soul are both restrained, as in, restrained to a table during this time.
The only upsides are:
1. Vaarsuvius's soulless body is "shielded from all harm" "for the duration" of Vaarsuvius's "stay". (They pride themselves on their good customer services, & the soul splice deal was a proof of concept thing for them.)
2. Lee, the Lawful Evil 1 of the 3 Archfiends, gives the assurance that "That vessel is your rightful property. Putting another soul into it would be a gross violation of our contract."
3. The fiends have a HD (Hell-Damned) Blood Plasma (with actual blood.) TV screen that they use to watch things just about anywhere on the mortal plane, which they allow others to view, like Vaarsuvius, Blackwing, & other fiends (Such as Sabine.) to watch. Things viewed this way, obviously, are not limited to where V's soulless body is.