i think the card is unnessecary since zombies are fast enough since we got zombie master and mezuki to abuse. nowadays nobody runs zombie-type beaters so there would be no critical point of using it. the only way it could speed up the deck is maybe with an il blud/supervise deck, but further more i dont think its worth running it. and thats with pure zombie decks.

in hybrid zombie decks there is no point of running it, since it has over 50% chance of being a dead card. the main backdraws are: that its once per turn, its continuous (so at activation and chained by mst, negated) and you need to have no monsters on the field while you have atleast 1 zombie-type monster in your hand that can be special summoned that way.

you can always use it for fun of course but i would recommend other cards that would fill the deck better, such like Book Of Life

does that make any sense?

Nah, it's not that good. Note that even Agents who are almost purely fairies with Hyperion and Kristya don't use Valhalla. Cards like this are only used for monsters that are big beaters, and even then it's kinda meh. Zombies almost always aren't pure...that's just the way they roll. They also kinda hve a space issue at times because of the hybrid factor, so throwing it in means you have to take out somethin better

well i like valhalla ( dont run it in agents but like it :D ) but just bcs fairies have kristya and hiperion 2 big beaters that can already decide an game
zombies dont have that beaters and they are fast and can revive all monsters from grave so no need for this card

Hmmm I believe zombies are way too fast themeselves.. Usually A player who knows how to play usually get the zombie combos to work withing 2-3 turns. he will not unnecessarily waste his deck space..

call of the mummy - special summon il blud - supervise - eff blud - get zombie master - eff zombie master - pitch mezuki to get plague - sync plague with il blud into: black brutdrago - eff supervise get il blud back - normal summon il blud - eff blud - get plague back - sync into scrap dragon - eff scrap pop black brutdrago - eff brutdrago get back il blud - eff blud - get back plague - sync into another black brutdrago - eff mezuki get back plague - sync into brionac - bounce opponents cards till 1 card left in hand - eff plague - sync into stardust..... GG!

i could go on with return from the different dimension but you get the idea.. the card was good in the good old days without synchro's and exceeds. now its only useable in il blud decks.

this card is pro nowadays for xyz'in too