What are all the ways - besides summoning - that devils can get to the material plane?

[Ryan Kappler]

I'm asking for a friend. :)

[DeathlessOne]

Being 'Called' through one of the many spells that actually pull them into the Material Realm, or through existing portals to the Astral Plane from the first layer of the Nine Hells, and then through a portal from the Astral Plane to the Material Realm. Or hitching a ride through a Planeshift spell by a local caster.

[Valandil Ancalime]

In an ap they had a portal to a layer of hell.

[WagnerSika]

In Hell Unleashed it is mentioned that the archdevil Moloch maintains a multiverse-wide network of stable planar portals and that there are "scores of such beachheads on Golarion".
The particular portal in Hell Unleashed acts as a permanent Gate to Hell.

[blahpers]

Contract devils can use plane shift once per day; I assume they leave it available in case an, ah, opportunity presents itself. I don't know of any others, though.

[Mudfoot]

Well of Many Worlds

[Meirril]

Its possible for a Wizard to cast Gate, or a very powerful devil/demon. This means something capable of throwing around a 9th level spell is near the gate but if a lesser creature wants to take a chance...

And then the typical GM "you can never do this but" kind of stuff. The stars align and open a rift. Magical explosion causes a gate to temporarly (or permanently) open. A Devil hitched a ride on one of Desna's super-moths. Some vile merchant made way too many shady and outright evil deals and became a devil without going to Hell.

Also with a place like Chelliax I'd imagine there are Gates to Hell permanently open. Probably with lots of guards on both ends. And you need paperwork to get through, in triplicate and you better have the officially approved bribes or you are not getting through without a full body cavity search and 'contraband' being 'confiscated'.

[Firebug]

Meirril wrote:

Its possible for a Wizard to cast Gate, or a very powerful devil/demon. This means something capable of throwing around a 9th level spell is near the gate but if a lesser creature wants to take a chance...

Unsurprisingly, Summoners do this better then Wizards. Something about being able to use their SLA 10+ times per day for Gate at level 19.

[Yqatuba]

Same way any extraplanar creature gets to the Prime. Use plane shift or gate, go through a portal, get sent there by some other spell (such as the violet line in prismatic spray)

[Adjoint]

Firebug wrote:

Unsurprisingly, Summoners do this better then Wizards. Something about being able to use their SLA 10+ times per day for Gate at level 19.

Though usually, at any given time, there is no more than ONE 19th level summoner on Golarion, and usually they are a PC, so they have a GM to deal with if they gate devils haphazardly.