Brindle described several species of the Nesogaster aculeatus-complex here:
Brindle A (1972) Dermaptera. Insects of Micronesia 5(2):97–171 (http://hbs.bpbmwebdata.org/pubs-online/pdf/iom5-2.pdf)
For Sulawesi the species would be the nominotypical N. aculeatus. Later, some species Brindle mentioned got synonymized by Steinmann in his World Catalogue of Dermaptera (1989).

However, this specimen:
https://www.inaturalist.org/observations/222406974
looks a bit different for me, the forceps base is broader than usual. Otherwise it fits well to the dark form of N. aculeatus, without yellow humeral spots on the elytrae and with just one tooth at the inner margin on the forceps (forms with 1 or 2 teeth are known).

There's also an intermediate form of N. aculeatus and N. intermedius from Borneo here:
https://www.inaturalist.org/observations/246733796

Possibly there are more species of the complex in the indopacific region than known.