LET'S GO!
Main concept here is to play regular pendulum spellcaster good stuff (Pend Magician, Majespecter, and Endymion) while having access to Magistus via 3 Theologia, 3 Verre, and Magistus Endymion. There's no streamlined combo, you gotta work with what you draw.
Need a lot of practice to gain full advantage on each hand you draw. The Theologia route is the most common way to access Magistus, any random low lv spellcaster can be an Artemis which you can slap Theologia on for another Artemis but as equip to search Verre. Verre can be pend summoned to search fusion spell for Aiwass. To extend the play, pend lineup comes in handy. Usually we use Cross-Sheep (Aiwass can trigger it) and Selene (best link climber).
Magistus: 3 Theologia and Verre (best cards), 1 each Magistus Endymion (Spell Power Mastery another target and Artemis equip access), Magistus Invocation (combo piece), Vritra (Verre another target, dead if drawn double of it with no Magistus in GY).
Pend Magician: Harmonizing, 3 Duelist Alliance, and Pendulum Call (best cards). Dragonpulse (Dai, Harmonizing, and Call target while being low lv for Artemis), White Wing (same reason and is a wind spellcaster for Majespecter), and Chronograph-Timegazer. Double Iris is there as another Duelist Alliance and Call target.
Majespecter: 3 Bunbuku (best card), 1 each of Kyubi, Ogama, and Tornado. We dont play the Majespecter spell lineup because of scaling problem. Yata, the spell searcher has same 5 scale with Ogama while Kyubi is scale 2 giving Bunbuku versatility. The spells also cant be used going first which means cant help Servant Endymion anyway.
Endymion: 3 Spell Power, 1 Servant (low lv for Artemis and wind spellcaster for Majespecter), 1 Mighty Master (free spell negation), 1 Magister Endymion (another servant target, low lv for Artemis, and has good scale). We dont run Jackal King as it has bad scale and monster negation is covered by Apollousa already (doesnt prevent Nibiru tho).
The rest of it is just good spells for Servant spell counter and Selene requirement like Spellbook engine (insta 2 spells), Unexpected Dai (free Artemis), Instant Fusion (free Artemis while triggering Cross-Sheep), Upstart, and Called by the Grave.
Extra deck is combo pieces with generic stuff. 3 Artemis (as spare, we use 2 in first turn), 2 Selene (combo piece and Accesscode follow-up), Masq (low effort interruption), Crowley (for plus).
Side deck depends on matchup.
Pros: Best deck. Majespecter is immune to Impermanence and Veiler.
Cons: Pend mechanic bad, need cards to put in scale and pend summon from extra deck is limited by extra/link zone. UNBAN KIRIN.