Titan is a graph database engine.
The company (Aurelius) developing Titan was acquired by DataStax in 2015. The project has not been updated since then.
Graph
Gremlin
http://titandb.io/
https://github.com/thinkaurelius/titan
http://s3.thinkaurelius.com/docs/titan/1.0.0/
@aureliusgraphs
Aurelius
US
2012
2015
DataStax
Open Source
Java
Berkeley DB, Cassandra, HBase
Apache v2