Under the OGL, OGC and PI are mutually exclusive categories. From the definition section 1(d):Under the OGL, the mention of product identity in open game content doesn't make it not PI.
"Open Game Content" means . . . but specifically excludes Product Identity
Yes. I've made this point in multiple posts.Umber hulk is product identity.
Umber hulks are also mentioned in the SRD.
Some posters seem to think that all of the SRD is OGC. They are wrong. The SRD itself makes this clear. (For clarity: I am talking about this SRD <https://media.wizards.com/2016/downloads/SRD-OGL_V1.1.pdf> I haven't looked at them all.)