Talos is the COSI central authentication (LDAP) server, the primary DNS server, and the primary DHCP server.
It is on VLAN 2 and can only be logged into from the 144/23 network.
Talos was created by Alan Beadle in Summer 2015 as a replacement for the old system that we had which was not working very well. The hardware failed in Summer 2017 and was replaced with new hardware that fall. The failure prompted the creation of Atlas as a failover server for DHCP and DNS.
Too complicated to say here, it has a lot of shit.
TL;DR, read the "Talos Book".