I think based up my information that this a Bagabo sword, a nice one at that. The sheath is definitely made in the PI looks like about 1900s, due to the thin can metal used to hold the 2 piece sheath. The monkey head carving makes sense due to the people from India having settled there. Know the cultural lore and influences.
What let you think in this way? Can you explain this a little bit further, maybe with examples?