I'm dissapointed that we don't have rules, I hoped we would. On the other hand a couple of observations.
First is that these books seem to be targeted to people who have never played before or have had only minimal experience. For brand new DMs, you probably don't need or want to start making new monsters right off the bat. If you include rules for making monsters it can give the false impression that making custom monsters is kind of a default, something everyone who wants to be a good DM should do.
The other is that I've always made custom monsters since long before we had any monster building rules or guidelines. IIRC they show up first in the 2012 DMG, at least as part of core set of rules. I always just grabbed an existing monster or two that were close enough and modified them to be what I wanted. We never needed a set of rules to make custom monsters.
I still wish they have provided the rules and other than being emphasizing what is required for new DMs, I don't have an answer. It would have been nice to have them but I'm also sure that in a short period of time someone will have reverse engineered them to come up with some guidelines.
First is that these books seem to be targeted to people who have never played before or have had only minimal experience. For brand new DMs, you probably don't need or want to start making new monsters right off the bat. If you include rules for making monsters it can give the false impression that making custom monsters is kind of a default, something everyone who wants to be a good DM should do.
The other is that I've always made custom monsters since long before we had any monster building rules or guidelines. IIRC they show up first in the 2012 DMG, at least as part of core set of rules. I always just grabbed an existing monster or two that were close enough and modified them to be what I wanted. We never needed a set of rules to make custom monsters.
I still wish they have provided the rules and other than being emphasizing what is required for new DMs, I don't have an answer. It would have been nice to have them but I'm also sure that in a short period of time someone will have reverse engineered them to come up with some guidelines.