Actually, this is not a unit but a single figure.
And it's a figure which doesn't actually appear in the game that he has so much influence over.
But he is there, making sure the game is played fairly and in accordance with the rules. He is
THE BLOOD BOWL REFEREE
Blood Bowl, like any other form of sport, is played according to a set of rules and it's the job of the Blood Bowl referee to make sure that the Players abide by those rules. Of course, as you would expect in such a violent, chaotic, pell mell of a game, the Ref has his work cut out trying to keep tabs on what is going on all over the pitch. Players are quick to exploit the fact that most Refs don't have eyes in the back of their head (unless they happen to be the mutated Chaos Ref, Foureye Cotchya'atit, who does actually have 2 eyes in the back of his head).
Dwarf Ref, Buska Blutfast, does not have eyes in the back of his head
It takes a special type of character to want to be a Blood Bowl Ref. Strangely enough for someone who has to be able to interpret and enforce the Rules of the Game, a lack of intellect is probably an advantage (you would need to be pretty stupid to want to do the job in the first place). Unfortunately, the experiment introduced by the NAF (Nuffle Amorical Football) League Commissioners of encouraging each race to provide a Ref to officiate games failed miserably when the only Snotling to ever take charge of a match, Squeaky Meeky, was accidentally eaten at the start of the game between the Dwarf team, The KazaK Kruisers and the Orc team, The Greenboyz Duckers, by the Duckers' Troll, Gampful Bumpful.
The best Refs tend to be former players, who have survived a game, with all their faculties still intact. Some, however, unfortunately forget that they are now Refs and get carried away with what is going on the pitch, as happened to Ogre Ref, CrudFit Manmasher, who reacting to his own whistle for the start of the match, proceeded to clobber 5 linemen of the Human Goldenballs team. When Crudfit finally remembered he was supposed to be officiating as opposed to fouling, he had no option but to send himself off for his illegal play (because fouling is illegal in Blood Bowl) and the match had to be abandoned.
It's a dangerous job, being a Blood Bowl Ref, and in addition to the mayhem on the pitch, sometimes the Crowd can get carried away (if a "2" is rolled on the Kick Off Table) and incapacitate the Ref (usually in a particularly brutal fashion as payback for an "erroneous decision" that the Ref made against their particular team). The replacement Ref is usually suitably kowtowed that he will turn a blind eye to a Foul Play carried out that half by either team, unless, of course, the Player rolls a "1" and in those circumstances even the most terrified Ref will send the Offender off rather than risk the wrath of Nuffle.
It has to be said that a Blood Bowl Ref is not a particularly well paid job and consequently, it comes as little surprise that some will be tempted to receive a little "backhander" from one or both Coaches, who use the filthy lucre to influence the Ref's decision where one of their Players gets caught in the act of putting his boot into an opponent's reproductive organs.
Normally if a Player rolls a double on a Foul play, then they will be sent to the Locker Rooms and take no further part in the game, but if the Ref has had his pockets lined in advance then anything but a "1" will allow the Player to remain on the field.
"Technically you have just committed a breach of Rule 26, paragraph B, sub-paragraph (iii) but I'm prepared to overlook it on this occasion, if you promise not to do it again!"
So love'em or hate'em, the game just wouldn't be the Game without the Blood Bowl Ref!