As an alternative to LHC, the same can be done by going to level 130 monsters to grind for level 130 armour and weapons. Muspell are the armour and Jaihin are the weapons.
Thanks for noticing. I generally use Von Leon equips since they are guarantees when bought from the shop rather than pulling your hair out trying to find a Muspell/ Jaihin.
Years ago in the Unlimited Update (KMS version of Unleashed with Xenon and Demon Avenger,) Arkarium's summons had their physical attack immunities removed. Fast forward 6 years and we still hadn't received the update. It is about time Arkarium gets an update.