You can set up the system on multiple devices for convenience to the extent that security can be ensured, such as a smartphone and a PC.

However, if you register multiple times, your previous settings will be invalidated, so you must use the same authentication seed and set it for all applications, as shown on the page linked below.
https://icts.nagoya-u.ac.jp/en/services/nuid/CAS/regist-multi.html