A Combo Primer - Sisay, Weatherlight Captain & Jegantha, the Wellspring

2020/04/09

This is a Primer on how to go infinite with Sisay, Weatherlight Captain as your commander and Jegantha, the Wellspring as your companion.

Step 0 - Prerequisites

You need to have Sisay, Weatherlight Captain and Jegantha, the Wellspring on the battlefield. Jegantha must not have summoning sickness.

Step 1

Sisay, Weatherlight Captain is a 4/4 due to Jegantha, i.e. legendary colors {R}{G}, on the field.

• Tap Jegantha for {W}{U}{B}{R}{G}.
• Use the {W}{U}{B}{R}{G} to activate Sisay's ability and find Kiora, Behemoth Beckoner or Kiora, Master of the Depths.

Step 2

Sisay, Weatherlight Captain is a 5/5 due to Jegantha and Kiora, i.e. legendary colors {U}{R}{G}, on the field.

• Activate your chosen Kiora to untap Jegantha.
• Tap Jegantha for {W}{U}{B}{R}{G}.
• Use the {W}{U}{B}{R}{G} to activate Sisay's ability and find Oath of Teferi exiling a land e.g. a Plains or another permanent not in use for this loop.

Step 3

Sisay, Weatherlight Captain is a 6/6 due to Jegantha, Kiora and Oath, i.e. legendary colors {W}{U}{R}{G}, on the field.

• With Oath of Teferi on the field, Activate your chosen Kiora to untap Jegantha another time.
• Tap Jegantha for {W}{U}{B}{R}{G}.
• Use the {W}{U}{B}{R}{G} to activate Sisay's ability and find Aminatou, the Fateshifter.

Step 4

Sisay, Weatherlight Captain is a 7/7 due to Jegantha, Kiora, Oath and Aminatou, i.e. legendary colors {W}{U}{B}{R}{G}, on the field.

• Activate Aminatou to blink Kiora, allowing for 2 new untaps and retain the remaining 1 blink of Aminatou.
• Activate your chosen Kiora to untap Jegantha, leaving 1 untap activation.
• Tap Jegantha for {W}{U}{B}{R}{G}.
• Use the {W}{U}{B}{R}{G} to activate Sisay's ability and find Teferi, Hero of Dominaria.

Step 5

Sisay, Weatherlight Captain is a 7/7 due to Jegantha, Kiora, Oath and Aminatou, i.e. legendary colors {W}{U}{B}{R}{G}, on the field.

• Activate your chosen Kiora to untap Jegantha.
• Tap Jegantha for {W}{U}{B}{R}{G}.
• Activate Aminatou to blink Kiora, allowing for 2 new untaps and no more blinks of Aminatou.
• Activate your chosen Kiora to untap Jegantha.
• Tap Jegantha for {W}{U}{B}{R}{G}. You have 2x {W}{U}{B}{R}{G} in pool.
• Activate your chosen Kiora to untap Jegantha.
• Tap Jegantha for {W}{U}{B}{R}{G}. You have 3x {W}{U}{B}{R}{G} in pool.
• Activate Teferi, Hero of Dominaria to put Aminatou, the Fateshifter back into your library.
• Use the {W}{U}{B}{R}{G} to activate Sisay's ability and find Aminatou, the Fateshifter. You have 2x {W}{U}{B}{R}{G} in pool.
• Activate Aminatou to blink Kiora and Teferi to reset their loyality abilities.

Step 6

You can now enter a loop where

• You use Aminatou, the Fateshifter to blink both Kiora and Teferi,
• then use Kiora to untap Jegantha twice each iteration yielding you 2x {W}{U}{B}{R}{G},
• the use Teferi to put Aminatou back into your library and
• activate Sisay, Weatherlight Captain to find her again and put her on the battlefield.

Each repetition of this loop nets you {W}{U}{B}{R}{G} so that you have infinite mana.
With infinite mana you can leave out Kiora and Jegantha and instead tutor for another payoff that you'll blink in your Aminatou, the Fateshifter / Teferi, Hero of Dominaria loop winning you the game.
In principle you can use any planeswalker, legendary creature with significant ETB or even Oath of Kaya.

Note that if you prefer to cast spells instead you can also use Teferi's +1 ability to draw your deck and use your infinite mana to loop suite of spells.

Conclusion

With Sisay, Weatherlight Captain as your commander and Jegantha, the Wellspring as your companion you have an extremely consistent game winning combo in your command / companion zone. That's pretty cool
Now is this broken, ban worthy or even just better than a version of the deck that runs Jegantha, the Wellspring in the 99?
I guess that depends on the rest of your build. Using Jegantha as companion means you're not only giving up on Nicol Bolas, Dragon God as a combo piece but also on some important pieces of protection like Grand Abolisher or, particularly for Sisay, Dosan the Falling Leaf.