About that Ainz-sama, how about we transport them into my guardian's arena?"
Ainz thought about what Shalltear said for a second and then firmly answered.
"Rejected, if we lose control of a guardian there we will have no way of bringing them back or even killing them."
A guardian's arena referred to the part of Nazarick where the floor guardians would fight with any invaders that came into Nazarick if they were of a high enough caliber. Inside their arena a floor guardian was nigh invincible when compared to outside of their arena. With the exception of Victim whose arena didn't strengthen him so much as the other fellows on his floor, a floor guardian inside his arena could easily take on 20 level 100 players and had the strength of a semi raid-boss.
In Shalltear's case she would face them inside the 'Blood fest Ballroom', where all players would continually be drained off their health whilst fighting her and her high-level undead minions. This along with her Spuit Lance and the fact that she could consume one of her six vampire brides' blood to restore her health completely made it possible to out-sustain even the strongest parties.
In Demiurge's case his 'Devil's Lobby' had a very nasty mechanism where the floor was actually the mouth of an enormous demon. Every two minutes there would be a magic activation that disabled all forms of flying and levitation for all creatures except for demonic creatures. If the curse was not dispelled within ten seconds the floor would open and the players would fall into the mouth where repeated instant-death magic was cast on them till they perished. Combine this with the barrage of AOE lava attacks and constant assault from flying demons and you had a veritable raid nightmare.
Ainz smiled as he reminisced about how much fun Peroronchino-san and Ulbert Alain Odle-san seemed to have as they were developing these mechanics back in the day.
Weren't those two being a little bit too sadistic with their arenas? Then again I did setup the Avatars in the Treasure room to attack anyone with the ring of Ainz Ooal Gown so I can't judge too much.
The reason that Ainz wished to avoid making the guardians arenas the battleground for defeating this enemy was twofold. First off there was a considerable amount of money that needed to be paid to activate an arena. In the old days it would have been an insignificant amount but now it was too much to use carelessly.
Secondly, though in YGGDRASIL you couldn't affect a floor guardian with a World Item whilst they are inside their arena, with the exception of world items like World Savior which did direct damage instead of effects− this was to prevent guilds constantly destroying each other's bases using just one world class item. But here in this new world there was no guarantee that the rule still applied. Which meant that if a guardian could be mind-controlled inside of their own arena, then Nazarick would have no way to stop them− since they did not possess enough level 100 members to take on a guardian inside of their arena without the use of another world item and even then it was risky.
"Looks like no matter what I'll have to wrap my hand in cloth and stick it in the flame to see if it catches fire. Well we'll have to burn that bridge when we get to it. For now let's focus on getting the proper Intel first. To charge at an enemy without clear understanding of their capabilities is just foolish."
"You are right as always Ainz-sama. The best thing would be to approach the problem the same way as we did in the kingdom."
"You mean send a small scouting group to their country to collect valuable Intel, layouts, population numbers and military strength?"
"Exactly so Ainz-sama."
"Though I do agree with the approach, the question we have to answer next is: who will go?"