DLL-docs.txt

OpenVS4.dll
Initialize
Should return zero if no errors are found.
Pass L"Ђ{(KEY-INFORMATION-HERE)}" for successful initialization. Run any program that uses the Vocaloid4 API from API monitor. Then go to API monitor -> first stack in params -> "LPWSTR" value.
alternativey you can find this key info in your registry. go to HKEY_CURRENT_USER\Software\VocaloidApi4 and the folder in there will have the name of the key thingo you gotta pass to it.

On a successful startup, OpenVS4's Initialize function will call a number of other functions from the other VocaloidApi4 DLLs. It can take a few seconds to load even in a minimal program.

After Initialize is complete, call "CreateOpenVS".
This returns a pointer to the virtual function table for the program.
Virtual functions 6, 7 and 8 allow other virtual function tables to be loaded.

Terminate also calls va_DSE4.dll!DSETerminate and another one i can't remember right now im on a different computer ok

va_DSE4.dll
"DSESetDBMPath" is used to locate the Vocaloid's DBM file.
"DSEDoStepSynthesis" seems to be responsible for the actual voice synthesis.