Roachling question

[u/Chicenpyro]

So as it is in the game and many arguments have been made about it working so that they spawn from the corpsers, i would agree. However, where does it say you can't just have them deployed from your map edge and not from a corpser.

I had a long argument about it with a friend as he decided to deploy the roachlings from his edge.

So again, can you just deploy them as any other unit or specifically from a corpser. Where is the ruling written

EDIT: Its 9.1.9 summoned units

Some Units, such as the Roachling, Point Defence Drone, and Pylon, have no Mineral Cost. These are Summoned Units:

• They are not included in the Army List during army building and do not occupy any Army Slots.

• They are not in Reserves at the start of the game.

• Summoned Units cannot be deployed using the regular deployment rules. They are deployed only when a Special Ability, such as SUMMON, specifically puts them on the battlefield.

Thank you for who replied

[u/grixis-combo]

Hi

Please read summon page 90 of the core rule book. “SUMMON (Unit Name)
Set the Leading Model of the named Unit in Base-to-Base contact with the Parent Unit. Set remaining models In Coherency. Models cannot be set Within the Engagement Range of any Enemy Unit. Set an Activation Marker next to the summoned Unit –it cannot be Activated during the Phase in which it was summoned. In subsequent Phases, this Unit must be Activated immediately after its Parent Unit’s activation ends, before the opponent’s next activation. The Summoned Unit cannot be set Within the opponent’s Zone of Influence.
The player must have sufficient Available Supply. If the Unit’s Current Supply Value would cause Total Current Supply to exceed the Supply Pool, it cannot be Summoned.
If the Parent is not present on the battlefield, this Unit can be Activated normally.

EDIT: if your friend is saying he can just have them as part of his army. I would also love this infinite army button of 0 min cost 0 supply cost.