The most reliable repeatable route is the desert Archaeological Site. Every generated variant contains a gilded chest with one or two Cells, and its six ordinary suspicious-sand blocks each offer an additional 1/29 Cell roll. If commands are enabled, use /locate structure mega_showdown:archaeological_site to find the nearest one.

Other guaranteed structure sources include the Wishing Weald, the upper storage barrel in the jungle Observatory, and two documented Cells in the Team Galactic Eterna Building. The maintained Zygarde Cell item page lists probabilistic raid, archaeology, and Turnback Cave sources without turning this walkthrough into a duplicated loot table.

Fill a 3x3 crafting grid with nine Cells to make one Zygarde Core. One Core can also be crafted back into nine Cells, so check the intended form before converting a large stack.

Right-click with the Cube while you are not targeting a Pokémon or Reassembly Unit. Put Cells in the left slot and Cores in the right slot.

For an ordinary 10% Zygarde, load exactly nine Cells and one Core.

Use the loaded Cube on an idle Reassembly Unit. The machine consumes the selected quantities and enters the matching processing state. Ordinary 10% takes two minutes, ordinary 50% takes five minutes, and Power Construct takes ten minutes.

The unit changes to a form-specific finished state when processing completes.

Hold the Poké Ball you want associated with Zygarde and use it on the finished Reassembly Unit. The machine consumes one ball, creates the selected Zygarde, adds it through player storage, and resets to idle.

Load a Cube with 49 Cells and one Core, then repeat the Reassembly Unit and Poké Ball sequence. This route takes five minutes and produces ordinary 50% Zygarde without Power Construct.

Fill the Cube to its capacity of 95 Cells and five Cores. Use it on an idle Reassembly Unit and wait ten minutes. The result is a 50% Zygarde with Power Construct, not a permanently Complete-form Pokémon.

Enter battle with the Power Construct Zygarde and reduce it to half of its maximum HP or below. At the end of the turn, Power Construct changes 10% or 50% Zygarde into Complete Forme for that battle.

Use an empty Cube on your owned ordinary 10% or 50% Zygarde. The Cube stores that Pokémon and becomes filled. Use the filled Cube on an idle Reassembly Unit to recover the components: 9 Cells and one Core from 10%, or 49 Cells and one Core from 50%.

Using the Cube directly on an owned Power Construct Zygarde toggles it between its 10% and 50% configurations instead of storing it. Verify move, held-item, friendship, and other state preservation before relying on the toggle for a trained Pokémon.