As he witnessed the Spirit Object's emergence, he also breathed a sigh of relief, grateful that it wasn't some catastrophic being. Then he added, "The power of that New King of Orlan isn't too strong, and the tier of the Death Knights he can summon isn't outrageously high. However, these Knights are indestructible, which makes them tough to deal with."
"..."
Leonard Churchill didn't need to be told, as he was already familiar with them.
Not to mention the knight patterns on the murals, hadn't he encountered those S-class Catastrophes, the Secret Keepers, in the Grand Cemetery Labyrinth, with exactly the same appearance?
Moreover, due to the limitations in the Alternate Dimension at that time, those Catastrophes were only Second Tier.
But now, looking at this Undead Army, the ranks were uniformly Fourth or Fifth Tier...
And the tiers of those emerging later were becoming even higher.