Answer

If you mean the Jain monastic order Achalgaccha (also called Anchalgacch or Vidhipaksh), its traditional line of leading monks begins with Acharya Aryarakshitsuri. A commonly listed succession includes Jayasimhasuri, Dharmaghoshasuri, Mahendrasinhsuri, Simhaprabhasuri, Ajitasinhsuri, Devendrasinhsuri, Dharmaprabhasuri, Simhatilaksuri, Mahendraprabhasuri, Merutungasuri, Jayakirtisuri, Jayakesarisuri, Siddhantasagarsuri, Bhavasagarsuri, Gunanidhansuri, Dharmamurtisuri, and Kalyansagarsuri. ( jainqq.org)

Explanation

Achalgaccha was not one single monk, but a Jain monastic lineage with many ācāryas and monks over time. Sources on its history also mention monks such as Mahendraprabhasuri, Merutungasuri, Jayakesarisuri, Gajalabh, Samayalabh, Harshalabh, Jayalabh, and Maanikyalabh in its branches and scholarly tradition. ( en.wikipedia.org)

Takeaway

So, the “monks in Achalgaccha” refers to a long Jain lineage of acharyas and muni-scholars, not just one or two names. The most important early name is Aryarakshitsuri. ( jainqq.org)